81238507 has 32 divisors (see below), whose sum is σ = 102703104. Its totient is φ = 62726400.

The previous prime is 81238501. The next prime is 81238523. The reversal of 81238507 is 70583218.

It is a cyclic number.

It is not a de Polignac number, because 81238507 - 2³ = 81238499 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 (81238501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 204433 + ... + 204829.

It is an arithmetic number, because the mean of its divisors is an integer number (3209472).

Almost surely, 2^81238507 is an apocalyptic number.

81238507 is a deficient number, since it is larger than the sum of its proper divisors (21464597).

81238507 is a wasteful number, since it uses less digits than its factorization.

81238507 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 499.

The product of its (nonzero) digits is 13440, while the sum is 34.

The square root of 81238507 is about 9013.2406491783. The cubic root of 81238507 is about 433.0991297874.

The spelling of 81238507 in words is "eighty-one million, two hundred thirty-eight thousand, five hundred seven".