81703521 has 27 divisors (see below), whose sum is σ = 124319377. Its totient is φ = 51703080.

The previous prime is 81703499. The next prime is 81703537. The reversal of 81703521 is 12530718.

The square root of 81703521 is 9039.

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

It is not a de Polignac number, because 81703521 - 2⁹ = 81703009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81703541) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 623626 + ... + 623756.

Almost surely, 2^81703521 is an apocalyptic number.

81703521 is the 9039-th square number.

81703521 is the 4520-th centered octagonal number.

It is an amenable number.

81703521 is a deficient number, since it is larger than the sum of its proper divisors (42615856).

81703521 is a wasteful number, since it uses less digits than its factorization.

81703521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 314 (or 157 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 27.

The cubic root of 81703521 is about 433.9239197127.

The spelling of 81703521 in words is "eighty-one million, seven hundred three thousand, five hundred twenty-one".