31988779919 has 2 divisors, whose sum is σ = 31988779920. Its totient is φ = 31988779918.

The previous prime is 31988779913. The next prime is 31988779931. The reversal of 31988779919 is 91997788913.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 31988779919 - 2¹² = 31988775823 is a prime.

It is a super-2 number, since 2×31988779919² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31988779913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15994389959 + 15994389960.

It is an arithmetic number, because the mean of its divisors is an integer number (15994389960).

Almost surely, 2^31988779919 is an apocalyptic number.

31988779919 is a deficient number, since it is larger than the sum of its proper divisors (1).

31988779919 is an equidigital number, since it uses as much as digits as its factorization.

31988779919 is an evil number, because the sum of its binary digits is even.

The product of its digits is 61725888, while the sum is 71.

The spelling of 31988779919 in words is "thirty-one billion, nine hundred eighty-eight million, seven hundred seventy-nine thousand, nine hundred nineteen".