81164642 has 8 divisors (see below), whose sum is σ = 131112156. Its totient is φ = 37460592.

The previous prime is 81164617. The next prime is 81164651. The reversal of 81164642 is 24646118.

It can be written as a sum of positive squares in 2 ways, for example, as 79727041 + 1437601 = 8929^2 + 1199^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×81164642² = 13175398221976328, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81164599 and 81164608.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1560833 + ... + 1560884.

Almost surely, 2^81164642 is an apocalyptic number.

81164642 is a deficient number, since it is larger than the sum of its proper divisors (49947514).

81164642 is a wasteful number, since it uses less digits than its factorization.

81164642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3121732.

The product of its digits is 9216, while the sum is 32.

The square root of 81164642 is about 9009.1421345209. The cubic root of 81164642 is about 432.9678268333.

The spelling of 81164642 in words is "eighty-one million, one hundred sixty-four thousand, six hundred forty-two".