81515960100 has 243 divisors, whose sum is σ = 264878079921. Its totient is φ = 20967854400.

The previous prime is 81515960087. The next prime is 81515960111. The reversal of 81515960100 is 106951518.

The square root of 81515960100 is 285510.

It is a perfect power (a square), and thus also a powerful number.

81515960100 is a `hidden beast` number, since 8 + 1 + 51 + 596 + 0 + 10 + 0 = 666.

It can be written as a sum of positive squares in only one way, i.e., 29345745636 + 52170214464 = 171306^2 + 228408^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 265524147 + ... + 265524453.

Almost surely, 2^81515960100 is an apocalyptic number.

81515960100 is the 285510-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81515960100

81515960100 is an abundant number, since it is smaller than the sum of its proper divisors (183362119821).

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

81515960100 is a wasteful number, since it uses less digits than its factorization.

81515960100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 696 (or 348 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 36.

Multiplying 81515960100 by its sum of digits (36), we get a square (2934574563600 = 1713060²).

81515960100 divided by its sum of digits (36) gives a square (2264332225 = 47585²).

The spelling of 81515960100 in words is "eighty-one billion, five hundred fifteen million, nine hundred sixty thousand, one hundred".