31121357 has 2 divisors, whose sum is σ = 31121358. Its totient is φ = 31121356.

The previous prime is 31121341. The next prime is 31121371. The reversal of 31121357 is 75312113.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23174596 + 7946761 = 4814^2 + 2819^2 .

It is a cyclic number.

It is not a de Polignac number, because 31121357 - 2⁴ = 31121341 is a prime.

It is a super-3 number, since 3×31121357³ (a number of 23 digits) contains 333 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31121557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15560678 + 15560679.

It is an arithmetic number, because the mean of its divisors is an integer number (15560679).

Almost surely, 2^31121357 is an apocalyptic number.

It is an amenable number.

31121357 is a deficient number, since it is larger than the sum of its proper divisors (1).

31121357 is an equidigital number, since it uses as much as digits as its factorization.

31121357 is an evil number, because the sum of its binary digits is even.

The product of its digits is 630, while the sum is 23.

The square root of 31121357 is about 5578.6518980843. The cubic root of 31121357 is about 314.5474546375.

The spelling of 31121357 in words is "thirty-one million, one hundred twenty-one thousand, three hundred fifty-seven".