31821208225 has 9 divisors (see below), whose sum is σ = 39459404217. Its totient is φ = 25456253040.

The previous prime is 31821208213. The next prime is 31821208249. The reversal of 31821208225 is 52280212813.

The square root of 31821208225 is 178385.

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

It can be written as a sum of positive squares in 4 ways, for example, as 128663649 + 31692544576 = 11343^2 + 178024^2 .

It is not a de Polignac number, because 31821208225 - 2⁹ = 31821207713 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 874087 + ... + 909763.

Almost surely, 2^31821208225 is an apocalyptic number.

31821208225 is the 178385-th square number.

31821208225 is the 89193-rd centered octagonal number.

It is an amenable number.

31821208225 is a deficient number, since it is larger than the sum of its proper divisors (7638195992).

31821208225 is an frugal number, since it uses more digits than its factorization.

31821208225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71364 (or 35682 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 34.

The spelling of 31821208225 in words is "thirty-one billion, eight hundred twenty-one million, two hundred eight thousand, two hundred twenty-five".