31890389 has 2 divisors, whose sum is σ = 31890390. Its totient is φ = 31890388.

The previous prime is 31890371. The next prime is 31890407. The reversal of 31890389 is 98309813.

It is a balanced prime because it is at equal distance from previous prime (31890371) and next prime (31890407).

It can be written as a sum of positive squares in only one way, i.e., 25300900 + 6589489 = 5030^2 + 2567^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31890389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31890349) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15945194 + 15945195.

It is an arithmetic number, because the mean of its divisors is an integer number (15945195).

Almost surely, 2^31890389 is an apocalyptic number.

It is an amenable number.

31890389 is a deficient number, since it is larger than the sum of its proper divisors (1).

31890389 is an equidigital number, since it uses as much as digits as its factorization.

31890389 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 46656, while the sum is 41.

The square root of 31890389 is about 5647.1576036091. The cubic root of 31890389 is about 317.1173027651.

The spelling of 31890389 in words is "thirty-one million, eight hundred ninety thousand, three hundred eighty-nine".