81500784 has 40 divisors (see below), whose sum is σ = 215684112. Its totient is φ = 26503680.

The previous prime is 81500761. The next prime is 81500801. The reversal of 81500784 is 48700518.

It is a happy number.

It is a super-2 number, since 2×81500784² = 13284755585229312, 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 7 ways as a sum of consecutive naturals, for example, 18739 + ... + 22674.

Almost surely, 2^81500784 is an apocalyptic number.

It is an amenable number.

81500784 is an abundant number, since it is smaller than the sum of its proper divisors (134183328).

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

81500784 is a wasteful number, since it uses less digits than its factorization.

81500784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41465 (or 41459 counting only the distinct ones).

The product of its (nonzero) digits is 8960, while the sum is 33.

The square root of 81500784 is about 9027.7784642735. The cubic root of 81500784 is about 433.5647132497.

The spelling of 81500784 in words is "eighty-one million, five hundred thousand, seven hundred eighty-four".