15611561020 has 24 divisors (see below), whose sum is σ = 35764667568. Its totient is φ = 5676931200.

The previous prime is 15611560961. The next prime is 15611561081. The reversal of 15611561020 is 2016511651.

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 15611561020.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35480601 + ... + 35481040.

It is an arithmetic number, because the mean of its divisors is an integer number (1490194482).

Almost surely, 2^15611561020 is an apocalyptic number.

15611561020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

15611561020 is an abundant number, since it is smaller than the sum of its proper divisors (20153106548).

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

15611561020 is a wasteful number, since it uses less digits than its factorization.

15611561020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70961661 (or 70961659 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 28.

The spelling of 15611561020 in words is "fifteen billion, six hundred eleven million, five hundred sixty-one thousand, twenty".