81438580 has 24 divisors (see below), whose sum is σ = 171924480. Its totient is φ = 32403360.

The previous prime is 81438563. The next prime is 81438593. The reversal of 81438580 is 8583418.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6840 + ... + 14479.

It is an arithmetic number, because the mean of its divisors is an integer number (7163520).

Almost surely, 2^81438580 is an apocalyptic number.

It is an amenable number.

81438580 is an abundant number, since it is smaller than the sum of its proper divisors (90485900).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81438580 is a wasteful number, since it uses less digits than its factorization.

81438580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21519 (or 21517 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 37.

The square root of 81438580 is about 9024.3326623081. The cubic root of 81438580 is about 433.4543816990.

The spelling of 81438580 in words is "eighty-one million, four hundred thirty-eight thousand, five hundred eighty".