81499252 has 6 divisors (see below), whose sum is σ = 142623698. Its totient is φ = 40749624.

The previous prime is 81499219. The next prime is 81499289. The reversal of 81499252 is 25299418.

It can be written as a sum of positive squares in only one way, i.e., 76807696 + 4691556 = 8764^2 + 2166^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10187403 + ... + 10187410.

Almost surely, 2^81499252 is an apocalyptic number.

It is an amenable number.

81499252 is a deficient number, since it is larger than the sum of its proper divisors (61124446).

81499252 is a wasteful number, since it uses less digits than its factorization.

81499252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20374817 (or 20374815 counting only the distinct ones).

The product of its digits is 51840, while the sum is 40.

The square root of 81499252 is about 9027.6936146504. The cubic root of 81499252 is about 433.5619966080.

The spelling of 81499252 in words is "eighty-one million, four hundred ninety-nine thousand, two hundred fifty-two".