181866810681 has 32 divisors (see below), whose sum is σ = 270973624320. Its totient is φ = 120552827472.

The previous prime is 181866810677. The next prime is 181866810709. The reversal of 181866810681 is 186018668181.

It is a happy number.

It is not a de Polignac number, because 181866810681 - 2² = 181866810677 is a prime.

It is a super-2 number, since 2×181866810681² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (181866810661) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3512080 + ... + 3563486.

It is an arithmetic number, because the mean of its divisors is an integer number (8467925760).

Almost surely, 2^181866810681 is an apocalyptic number.

It is an amenable number.

181866810681 is a deficient number, since it is larger than the sum of its proper divisors (89106813639).

181866810681 is a wasteful number, since it uses less digits than its factorization.

181866810681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52162 (or 52156 counting only the distinct ones).

The product of its (nonzero) digits is 884736, while the sum is 54.

The spelling of 181866810681 in words is "one hundred eighty-one billion, eight hundred sixty-six million, eight hundred ten thousand, six hundred eighty-one".