15561551850 has 48 divisors (see below), whose sum is σ = 41561319072. Its totient is φ = 3830535360.

The previous prime is 15561551843. The next prime is 15561551861. The reversal of 15561551850 is 5815516551.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3988192 + ... + 3992091.

It is an arithmetic number, because the mean of its divisors is an integer number (865860814).

Almost surely, 2^15561551850 is an apocalyptic number.

15561551850 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

15561551850 is an abundant number, since it is smaller than the sum of its proper divisors (25999767222).

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

15561551850 is a wasteful number, since it uses less digits than its factorization.

15561551850 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7980311 (or 7980306 counting only the distinct ones).

The product of its (nonzero) digits is 150000, while the sum is 42.

The spelling of 15561551850 in words is "fifteen billion, five hundred sixty-one million, five hundred fifty-one thousand, eight hundred fifty".