18561549477786 has 32 divisors (see below), whose sum is σ = 42427626595200. Its totient is φ = 5303146377216.

The previous prime is 18561549477773. The next prime is 18561549477833. The reversal of 18561549477786 is 68777494516581.

It is a super-2 number, since 2×18561549477786² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4922151 + ... + 7832666.

It is an arithmetic number, because the mean of its divisors is an integer number (1325863331100).

Almost surely, 2^{18561549477786} is an apocalyptic number.

18561549477786 is an abundant number, since it is smaller than the sum of its proper divisors (23866077117414).

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

18561549477786 is a wasteful number, since it uses less digits than its factorization.

18561549477786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12789478.

The product of its digits is 2844979200, while the sum is 78.

The spelling of 18561549477786 in words is "eighteen trillion, five hundred sixty-one billion, five hundred forty-nine million, four hundred seventy-seven thousand, seven hundred eighty-six".