31381721253 has 24 divisors (see below), whose sum is σ = 46431839168. Its totient is φ = 20413233792.

The previous prime is 31381721213. The next prime is 31381721263. The reversal of 31381721253 is 35212718313.

It is a happy number.

31381721253 is a `hidden beast` number, since 3 + 1 + 381 + 7 + 21 + 253 = 666.

It is not a de Polignac number, because 31381721253 - 2¹⁰ = 31381720229 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31381721213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 332301 + ... + 416157.

Almost surely, 2^31381721253 is an apocalyptic number.

It is an amenable number.

31381721253 is a deficient number, since it is larger than the sum of its proper divisors (15050117915).

31381721253 is a wasteful number, since it uses less digits than its factorization.

31381721253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84873 (or 84870 counting only the distinct ones).

The product of its digits is 30240, while the sum is 36.

The spelling of 31381721253 in words is "thirty-one billion, three hundred eighty-one million, seven hundred twenty-one thousand, two hundred fifty-three".