31221829809 has 45 divisors (see below), whose sum is σ = 48375206737. Its totient is φ = 20067124896.

The previous prime is 31221829789. The next prime is 31221829813. The reversal of 31221829809 is 90892812213.

It is a happy number.

The square root of 31221829809 is 176697.

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 13974786225 + 17247043584 = 118215^2 + 131328^2 .

It is not a de Polignac number, because 31221829809 - 2⁵ = 31221829777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31221829109) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 46117579 + ... + 46118255.

Almost surely, 2^31221829809 is an apocalyptic number.

31221829809 is the 176697-th square number.

31221829809 is the 88349-th centered octagonal number.

It is an amenable number.

31221829809 is a deficient number, since it is larger than the sum of its proper divisors (17153376928).

31221829809 is an frugal number, since it uses more digits than its factorization.

31221829809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1424 (or 709 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 45.

The spelling of 31221829809 in words is "thirty-one billion, two hundred twenty-one million, eight hundred twenty-nine thousand, eight hundred nine".