81657653 has 16 divisors (see below), whose sum is σ = 102090240. Its totient is φ = 63452400.

The previous prime is 81657643. The next prime is 81657673. The reversal of 81657653 is 35675618.

It is not a de Polignac number, because 81657653 - 2⁴ = 81657637 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81657653.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81657623) by changing a digit.

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, 30998 + ... + 33528.

It is an arithmetic number, because the mean of its divisors is an integer number (6380640).

Almost surely, 2^81657653 is an apocalyptic number.

It is an amenable number.

81657653 is a deficient number, since it is larger than the sum of its proper divisors (20432587).

81657653 is a wasteful number, since it uses less digits than its factorization.

81657653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2968.

The product of its digits is 151200, while the sum is 41.

The square root of 81657653 is about 9036.4624162335. The cubic root of 81657653 is about 433.8427035146.

The spelling of 81657653 in words is "eighty-one million, six hundred fifty-seven thousand, six hundred fifty-three".