15990706656 has 72 divisors (see below), whose sum is σ = 45535712040. Its totient is φ = 5322951936.

The previous prime is 15990706649. The next prime is 15990706663. The reversal of 15990706656 is 65660709951.

It is an interprime number because it is at equal distance from previous prime (15990706649) and next prime (15990706663).

It is a tau number, because it is divible by the number of its divisors (72).

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 175266 + ... + 250398.

It is an arithmetic number, because the mean of its divisors is an integer number (632440445).

Almost surely, 2^15990706656 is an apocalyptic number.

15990706656 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 15990706656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22767856020).

15990706656 is an abundant number, since it is smaller than the sum of its proper divisors (29545005384).

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

15990706656 is a wasteful number, since it uses less digits than its factorization.

15990706656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75888 (or 75877 counting only the distinct ones).

The product of its (nonzero) digits is 3061800, while the sum is 54.

The spelling of 15990706656 in words is "fifteen billion, nine hundred ninety million, seven hundred six thousand, six hundred fifty-six".