1929771648 has 128 divisors (see below), whose sum is σ = 6509232000. Its totient is φ = 551356416.

The previous prime is 1929771647. The next prime is 1929771659. The reversal of 1929771648 is 8461779291.

It is a tau number, because it is divible by the number of its divisors (128).

It is a super-2 number, since 2×1929771648² = 7448037226849271808, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 1929771594 and 1929771603.

It is not an unprimeable number, because it can be changed into a prime (1929771647) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15693 + ... + 64076.

It is an arithmetic number, because the mean of its divisors is an integer number (50853375).

Almost surely, 2^1929771648 is an apocalyptic number.

1929771648 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1929771648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3254616000).

1929771648 is an abundant number, since it is smaller than the sum of its proper divisors (4579460352).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1929771648 is an equidigital number, since it uses as much as digits as its factorization.

1929771648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79799 (or 79781 counting only the distinct ones).

The product of its digits is 1524096, while the sum is 54.

The square root of 1929771648 is about 43929.1662566000. The cubic root of 1929771648 is about 1244.9979619650.

The spelling of 1929771648 in words is "one billion, nine hundred twenty-nine million, seven hundred seventy-one thousand, six hundred forty-eight".