81729325 has 12 divisors (see below), whose sum is σ = 103007668. Its totient is φ = 64310400.

The previous prime is 81729313. The next prime is 81729343. The reversal of 81729325 is 52392718.

It can be written as a sum of positive squares in 6 ways, for example, as 16410601 + 65318724 = 4051^2 + 8082^2 .

It is not a de Polignac number, because 81729325 - 2⁵ = 81729293 is a prime.

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 25272 + ... + 28321.

Almost surely, 2^81729325 is an apocalyptic number.

It is an amenable number.

81729325 is a deficient number, since it is larger than the sum of its proper divisors (21278343).

81729325 is a wasteful number, since it uses less digits than its factorization.

81729325 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53664 (or 53659 counting only the distinct ones).

The product of its digits is 30240, while the sum is 37.

The square root of 81729325 is about 9040.4272576024. The cubic root of 81729325 is about 433.9695962193.

The spelling of 81729325 in words is "eighty-one million, seven hundred twenty-nine thousand, three hundred twenty-five".