81438875 has 32 divisors (see below), whose sum is σ = 117072384. Its totient is φ = 55404000.

The previous prime is 81438839. The next prime is 81438881. The reversal of 81438875 is 57883418.

It is not a de Polignac number, because 81438875 - 2¹⁴ = 81422491 is a prime.

It is a super-2 number, since 2×81438875² = 13264580722531250, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 142340 + ... + 142910.

It is an arithmetic number, because the mean of its divisors is an integer number (3658512).

Almost surely, 2^81438875 is an apocalyptic number.

81438875 is a deficient number, since it is larger than the sum of its proper divisors (35633509).

81438875 is a wasteful number, since it uses less digits than its factorization.

81438875 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 756 (or 746 counting only the distinct ones).

The product of its digits is 215040, while the sum is 44.

The square root of 81438875 is about 9024.3490069921. The cubic root of 81438875 is about 433.4549050746.

The spelling of 81438875 in words is "eighty-one million, four hundred thirty-eight thousand, eight hundred seventy-five".