31287721379 has 4 divisors (see below), whose sum is σ = 31716320376. Its totient is φ = 30859122384.

The previous prime is 31287721373. The next prime is 31287721411. The reversal of 31287721379 is 97312778213.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 31287721379 - 2²⁴ = 31270944163 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31287721373) 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 3 ways as a sum of consecutive naturals, for example, 214299389 + ... + 214299534.

It is an arithmetic number, because the mean of its divisors is an integer number (7929080094).

Almost surely, 2^31287721379 is an apocalyptic number.

31287721379 is a deficient number, since it is larger than the sum of its proper divisors (428598997).

31287721379 is an equidigital number, since it uses as much as digits as its factorization.

31287721379 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 428598996.

The product of its digits is 889056, while the sum is 50.

The spelling of 31287721379 in words is "thirty-one billion, two hundred eighty-seven million, seven hundred twenty-one thousand, three hundred seventy-nine".