81645576 has 16 divisors (see below), whose sum is σ = 204114000. Its totient is φ = 27215184.

The previous prime is 81645563. The next prime is 81645581. The reversal of 81645576 is 67554618.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1700926 + ... + 1700973.

It is an arithmetic number, because the mean of its divisors is an integer number (12757125).

Almost surely, 2^81645576 is an apocalyptic number.

It is an amenable number.

81645576 is an abundant number, since it is smaller than the sum of its proper divisors (122468424).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81645576 is a wasteful number, since it uses less digits than its factorization.

81645576 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3401908 (or 3401904 counting only the distinct ones).

The product of its digits is 201600, while the sum is 42.

The square root of 81645576 is about 9035.7941543619. The cubic root of 81645576 is about 433.8213143103.

The spelling of 81645576 in words is "eighty-one million, six hundred forty-five thousand, five hundred seventy-six".