81604376 has 64 divisors (see below), whose sum is σ = 182952000. Its totient is φ = 33384960.

The previous prime is 81604357. The next prime is 81604423. The reversal of 81604376 is 67340618.

It is a congruent 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, 176786 + ... + 177246.

It is an arithmetic number, because the mean of its divisors is an integer number (2858625).

Almost surely, 2^81604376 is an apocalyptic number.

81604376 is the 7376-th pentagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81604376, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91476000).

81604376 is an abundant number, since it is smaller than the sum of its proper divisors (101347624).

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

81604376 is a wasteful number, since it uses less digits than its factorization.

81604376 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 612 (or 608 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 35.

The square root of 81604376 is about 9033.5140449329. The cubic root of 81604376 is about 433.7483303786.

The spelling of 81604376 in words is "eighty-one million, six hundred four thousand, three hundred seventy-six".