81515764 has 48 divisors (see below), whose sum is σ = 160114752. Its totient is φ = 36300000.

The previous prime is 81515747. The next prime is 81515767. The reversal of 81515764 is 46751518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81515767) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 324639 + ... + 324889.

It is an arithmetic number, because the mean of its divisors is an integer number (3335724).

Almost surely, 2^81515764 is an apocalyptic number.

It is an amenable number.

81515764 is a deficient number, since it is larger than the sum of its proper divisors (78598988).

81515764 is a wasteful number, since it uses less digits than its factorization.

81515764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 349 (or 325 counting only the distinct ones).

The product of its digits is 33600, while the sum is 37.

The square root of 81515764 is about 9028.6080876290. The cubic root of 81515764 is about 433.5912749637.

The spelling of 81515764 in words is "eighty-one million, five hundred fifteen thousand, seven hundred sixty-four".