81700457 has 4 divisors (see below), whose sum is σ = 82734720. Its totient is φ = 80666196.

The previous prime is 81700417. The next prime is 81700483. The reversal of 81700457 is 75400718.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81700457 - 2¹⁶ = 81634921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81700417) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 517013 + ... + 517170.

It is an arithmetic number, because the mean of its divisors is an integer number (20683680).

Almost surely, 2^81700457 is an apocalyptic number.

It is an amenable number.

81700457 is a deficient number, since it is larger than the sum of its proper divisors (1034263).

81700457 is a wasteful number, since it uses less digits than its factorization.

81700457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1034262.

The product of its (nonzero) digits is 7840, while the sum is 32.

The square root of 81700457 is about 9038.8305106358. The cubic root of 81700457 is about 433.9184953870.

The spelling of 81700457 in words is "eighty-one million, seven hundred thousand, four hundred fifty-seven".