81376520 has 64 divisors (see below), whose sum is σ = 187729920. Its totient is φ = 31739904.

The previous prime is 81376483. The next prime is 81376541. The reversal of 81376520 is 2567318.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 421544 + ... + 421736.

It is an arithmetic number, because the mean of its divisors is an integer number (2933280).

Almost surely, 2^81376520 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81376520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (93864960).

81376520 is an abundant number, since it is smaller than the sum of its proper divisors (106353400).

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

81376520 is a wasteful number, since it uses less digits than its factorization.

81376520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 414 (or 410 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 81376520 is about 9020.8935255882. The cubic root of 81376520 is about 433.3442495606.

The spelling of 81376520 in words is "eighty-one million, three hundred seventy-six thousand, five hundred twenty".