81894507 has 16 divisors (see below), whose sum is σ = 113127840. Its totient is φ = 52659200.

The previous prime is 81894499. The next prime is 81894511. The reversal of 81894507 is 70549818.

It is a cyclic number.

It is not a de Polignac number, because 81894507 - 2³ = 81894499 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (81894557) 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, 7207 + ... + 14687.

It is an arithmetic number, because the mean of its divisors is an integer number (7070490).

Almost surely, 2^81894507 is an apocalyptic number.

81894507 is a deficient number, since it is larger than the sum of its proper divisors (31233333).

81894507 is a wasteful number, since it uses less digits than its factorization.

81894507 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7614.

The product of its (nonzero) digits is 80640, while the sum is 42.

The square root of 81894507 is about 9049.5583870154. The cubic root of 81894507 is about 434.2617627778.

The spelling of 81894507 in words is "eighty-one million, eight hundred ninety-four thousand, five hundred seven".