81164643 has 16 divisors (see below), whose sum is σ = 127023360. Its totient is φ = 45125856.

The previous prime is 81164617. The next prime is 81164651. The reversal of 81164643 is 34646118.

It is not a de Polignac number, because 81164643 - 2⁸ = 81164387 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81160643) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 51453 + ... + 53006.

It is an arithmetic number, because the mean of its divisors is an integer number (7938960).

Almost surely, 2^81164643 is an apocalyptic number.

81164643 is a deficient number, since it is larger than the sum of its proper divisors (45858717).

81164643 is a wasteful number, since it uses less digits than its factorization.

81164643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104506.

The product of its digits is 13824, while the sum is 33.

The square root of 81164643 is about 9009.1421900201. The cubic root of 81164643 is about 432.9678286114.

The spelling of 81164643 in words is "eighty-one million, one hundred sixty-four thousand, six hundred forty-three".