81121504 has 24 divisors (see below), whose sum is σ = 160973568. Its totient is φ = 40239360.

The previous prime is 81121499. The next prime is 81121541. The reversal of 81121504 is 40512118.

It is a super-2 number, since 2×81121504² = 13161396822444032, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5917 + ... + 14044.

It is an arithmetic number, because the mean of its divisors is an integer number (6707232).

Almost surely, 2^81121504 is an apocalyptic number.

It is an amenable number.

81121504 is a deficient number, since it is larger than the sum of its proper divisors (79852064).

81121504 is a wasteful number, since it uses less digits than its factorization.

81121504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20098 (or 20090 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 22.

The square root of 81121504 is about 9006.7476927024. The cubic root of 81121504 is about 432.8911075642.

The spelling of 81121504 in words is "eighty-one million, one hundred twenty-one thousand, five hundred four".