31688869 has 2 divisors, whose sum is σ = 31688870. Its totient is φ = 31688868.

The previous prime is 31688861. The next prime is 31688939. The reversal of 31688869 is 96888613.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 29571844 + 2117025 = 5438^2 + 1455^2 .

It is an emirp because it is prime and its reverse (96888613) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31688869 - 2³ = 31688861 is a prime.

It is a super-2 number, since 2×31688869² = 2008368836998322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31688861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15844434 + 15844435.

It is an arithmetic number, because the mean of its divisors is an integer number (15844435).

Almost surely, 2^31688869 is an apocalyptic number.

It is an amenable number.

31688869 is a deficient number, since it is larger than the sum of its proper divisors (1).

31688869 is an equidigital number, since it uses as much as digits as its factorization.

31688869 is an evil number, because the sum of its binary digits is even.

The product of its digits is 497664, while the sum is 49.

The square root of 31688869 is about 5629.2867221345. The cubic root of 31688869 is about 316.4479207061.

It can be divided in two parts, 31 and 688869, that added together give a square (688900 = 830²).

The spelling of 31688869 in words is "thirty-one million, six hundred eighty-eight thousand, eight hundred sixty-nine".