31557109 has 2 divisors, whose sum is σ = 31557110. Its totient is φ = 31557108.

The previous prime is 31557077. The next prime is 31557121. The reversal of 31557109 is 90175513.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19847025 + 11710084 = 4455^2 + 3422^2 .

It is a cyclic number.

It is not a de Polignac number, because 31557109 - 2⁵ = 31557077 is a prime.

It is a super-2 number, since 2×31557109² = 1991702256875762, which contains 22 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 (31557139) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15778554 + 15778555.

It is an arithmetic number, because the mean of its divisors is an integer number (15778555).

Almost surely, 2^31557109 is an apocalyptic number.

It is an amenable number.

31557109 is a deficient number, since it is larger than the sum of its proper divisors (1).

31557109 is an equidigital number, since it uses as much as digits as its factorization.

31557109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4725, while the sum is 31.

The square root of 31557109 is about 5617.5714503689. The cubic root of 31557109 is about 316.0087223197.

The spelling of 31557109 in words is "thirty-one million, five hundred fifty-seven thousand, one hundred nine".