1871721648 has 80 divisors (see below), whose sum is σ = 5452805760. Its totient is φ = 614585664.

The previous prime is 1871721617. The next prime is 1871721661. The reversal of 1871721648 is 8461271781.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3390 + ... + 61277.

It is an arithmetic number, because the mean of its divisors is an integer number (68160072).

Almost surely, 2^1871721648 is an apocalyptic number.

1871721648 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 1871721648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2726402880).

1871721648 is an abundant number, since it is smaller than the sum of its proper divisors (3581084112).

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

1871721648 is a wasteful number, since it uses less digits than its factorization.

1871721648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64751 (or 64739 counting only the distinct ones).

The product of its digits is 150528, while the sum is 45.

The square root of 1871721648 is about 43263.3984795462. The cubic root of 1871721648 is about 1232.3869413414.

The spelling of 1871721648 in words is "one billion, eight hundred seventy-one million, seven hundred twenty-one thousand, six hundred forty-eight".