15991366440 has 256 divisors, whose sum is σ = 55753113600. Its totient is φ = 3593880576.

The previous prime is 15991366411. The next prime is 15991366463. The reversal of 15991366440 is 4466319951.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 15991366440.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 26344617 + ... + 26345223.

It is an arithmetic number, because the mean of its divisors is an integer number (217785600).

Almost surely, 2^15991366440 is an apocalyptic number.

15991366440 is a gapful number since it is divisible by the number (10) 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 15991366440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27876556800).

15991366440 is an abundant number, since it is smaller than the sum of its proper divisors (39761747160).

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

15991366440 is a wasteful number, since it uses less digits than its factorization.

15991366440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1104 (or 1100 counting only the distinct ones).

The product of its (nonzero) digits is 699840, while the sum is 48.

The spelling of 15991366440 in words is "fifteen billion, nine hundred ninety-one million, three hundred sixty-six thousand, four hundred forty".