81240575 has 12 divisors (see below), whose sum is σ = 108487848. Its totient is φ = 59992800.

The previous prime is 81240563. The next prime is 81240613. The reversal of 81240575 is 57504218.

It is not a de Polignac number, because 81240575 - 2⁸ = 81240319 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 124661 + ... + 125310.

It is an arithmetic number, because the mean of its divisors is an integer number (9040654).

Almost surely, 2^81240575 is an apocalyptic number.

81240575 is a deficient number, since it is larger than the sum of its proper divisors (27247273).

81240575 is a wasteful number, since it uses less digits than its factorization.

81240575 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 249994 (or 249989 counting only the distinct ones).

The product of its (nonzero) digits is 11200, while the sum is 32.

The square root of 81240575 is about 9013.3553685628. The cubic root of 81240575 is about 433.1028047335.

The spelling of 81240575 in words is "eighty-one million, two hundred forty thousand, five hundred seventy-five".