1261984416 has 288 divisors, whose sum is σ = 4354015680. Its totient is φ = 316485120.

The previous prime is 1261984411. The next prime is 1261984433. The reversal of 1261984416 is 6144891621.

It is a super-2 number, since 2×1261984416² = 3185209332453722112, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (1261984411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 43516690 + ... + 43516718.

It is an arithmetic number, because the mean of its divisors is an integer number (15118110).

Almost surely, 2^1261984416 is an apocalyptic number.

1261984416 is a gapful number since it is divisible by the number (16) 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 1261984416, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2177007840).

1261984416 is an abundant number, since it is smaller than the sum of its proper divisors (3092031264).

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

1261984416 is an equidigital number, since it uses as much as digits as its factorization.

1261984416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125 (or 52 counting only the distinct ones).

The product of its digits is 82944, while the sum is 42.

The square root of 1261984416 is about 35524.4199952652. The cubic root of 1261984416 is about 1080.6490200477.

The spelling of 1261984416 in words is "one billion, two hundred sixty-one million, nine hundred eighty-four thousand, four hundred sixteen".