15815680440 has 256 divisors, whose sum is σ = 58410270720. Its totient is φ = 3346168320.

The previous prime is 15815680393. The next prime is 15815680457. The reversal of 15815680440 is 4408651851.

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

It is a junction number, because it is equal to n+sod(n) for n = 15815680392 and 15815680401.

It is a congruent number.

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, 585717 + ... + 612123.

It is an arithmetic number, because the mean of its divisors is an integer number (228165120).

Almost surely, 2^15815680440 is an apocalyptic number.

15815680440 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 15815680440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29205135360).

15815680440 is an abundant number, since it is smaller than the sum of its proper divisors (42594590280).

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

15815680440 is a wasteful number, since it uses less digits than its factorization.

15815680440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26482 (or 26478 counting only the distinct ones).

The product of its (nonzero) digits is 153600, while the sum is 42.

The spelling of 15815680440 in words is "fifteen billion, eight hundred fifteen million, six hundred eighty thousand, four hundred forty".