15920661556 has 6 divisors (see below), whose sum is σ = 27861157730. Its totient is φ = 7960330776.

The previous prime is 15920661553. The next prime is 15920661557. The reversal of 15920661556 is 65516602951.

It can be written as a sum of positive squares in only one way, i.e., 11017861156 + 4902800400 = 104966^2 + 70020^2 .

It is a super-2 number, since 2×15920661556² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15920661553) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1990082691 + ... + 1990082698.

Almost surely, 2^15920661556 is an apocalyptic number.

It is an amenable number.

15920661556 is a deficient number, since it is larger than the sum of its proper divisors (11940496174).

15920661556 is a wasteful number, since it uses less digits than its factorization.

15920661556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3980165393 (or 3980165391 counting only the distinct ones).

The product of its (nonzero) digits is 486000, while the sum is 46.

The spelling of 15920661556 in words is "fifteen billion, nine hundred twenty million, six hundred sixty-one thousand, five hundred fifty-six".