18661143608890 has 16 divisors (see below), whose sum is σ = 33644323545120. Its totient is φ = 7452398543760.

The previous prime is 18661143608851. The next prime is 18661143608893. The reversal of 18661143608890 is 9880634116681.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (18661143608893) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1507355976 + ... + 1507368355.

It is an arithmetic number, because the mean of its divisors is an integer number (2102770221570).

Almost surely, 2^{18661143608890} is an apocalyptic number.

18661143608890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18661143608890 is a deficient number, since it is larger than the sum of its proper divisors (14983179936230).

18661143608890 is a wasteful number, since it uses less digits than its factorization.

18661143608890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3014724957.

The product of its (nonzero) digits is 11943936, while the sum is 61.

The spelling of 18661143608890 in words is "eighteen trillion, six hundred sixty-one billion, one hundred forty-three million, six hundred eight thousand, eight hundred ninety".