81632529 has 30 divisors (see below), whose sum is σ = 134054690. Its totient is φ = 49468320.

The previous prime is 81632527. The next prime is 81632549. The reversal of 81632529 is 92523618.

It can be written as a sum of positive squares in only one way, i.e., 55130625 + 26501904 = 7425^2 + 5148^2 .

It is not a de Polignac number, because 81632529 - 2¹ = 81632527 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 81632493 and 81632502.

It is not an unprimeable number, because it can be changed into a prime (81632527) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 5637 + ... + 13965.

Almost surely, 2^81632529 is an apocalyptic number.

It is an amenable number.

81632529 is a deficient number, since it is larger than the sum of its proper divisors (52422161).

81632529 is a wasteful number, since it uses less digits than its factorization.

81632529 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8363 (or 8343 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 81632529 is about 9035.0721635192. The cubic root of 81632529 is about 433.7982047985.

The spelling of 81632529 in words is "eighty-one million, six hundred thirty-two thousand, five hundred twenty-nine".