31889881 has 2 divisors, whose sum is σ = 31889882. Its totient is φ = 31889880.

The previous prime is 31889873. The next prime is 31889911. The reversal of 31889881 is 18898813.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27825625 + 4064256 = 5275^2 + 2016^2 .

It is an emirp because it is prime and its reverse (18898813) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31889881 - 2³ = 31889873 is a prime.

It is a super-2 number, since 2×31889881² = 2033929020388322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31889281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15944940 + 15944941.

It is an arithmetic number, because the mean of its divisors is an integer number (15944941).

Almost surely, 2^31889881 is an apocalyptic number.

It is an amenable number.

31889881 is a deficient number, since it is larger than the sum of its proper divisors (1).

31889881 is an equidigital number, since it uses as much as digits as its factorization.

31889881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 110592, while the sum is 46.

The square root of 31889881 is about 5647.1126250501. The cubic root of 31889881 is about 317.1156189093.

The spelling of 31889881 in words is "thirty-one million, eight hundred eighty-nine thousand, eight hundred eighty-one".