31356389 has 2 divisors, whose sum is σ = 31356390. Its totient is φ = 31356388.

The previous prime is 31356373. The next prime is 31356419. The reversal of 31356389 is 98365313.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23600164 + 7756225 = 4858^2 + 2785^2 .

It is a cyclic number.

It is not a de Polignac number, because 31356389 - 2⁴ = 31356373 is a prime.

It is a super-2 number, since 2×31356389² = 1966446262238642, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31356319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15678194 + 15678195.

It is an arithmetic number, because the mean of its divisors is an integer number (15678195).

Almost surely, 2^31356389 is an apocalyptic number.

It is an amenable number.

31356389 is a deficient number, since it is larger than the sum of its proper divisors (1).

31356389 is an equidigital number, since it uses as much as digits as its factorization.

31356389 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 58320, while the sum is 38.

The square root of 31356389 is about 5599.6775800040. The cubic root of 31356389 is about 315.3373022468.

The spelling of 31356389 in words is "thirty-one million, three hundred fifty-six thousand, three hundred eighty-nine".