31191089 has 2 divisors, whose sum is σ = 31191090. Its totient is φ = 31191088.

The previous prime is 31191047. The next prime is 31191101. The reversal of 31191089 is 98019113.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24601600 + 6589489 = 4960^2 + 2567^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31191089 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (31191689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15595544 + 15595545.

It is an arithmetic number, because the mean of its divisors is an integer number (15595545).

Almost surely, 2^31191089 is an apocalyptic number.

It is an amenable number.

31191089 is a deficient number, since it is larger than the sum of its proper divisors (1).

31191089 is an equidigital number, since it uses as much as digits as its factorization.

31191089 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944, while the sum is 32.

The square root of 31191089 is about 5584.8982980892. The cubic root of 31191089 is about 314.7822094109.

The spelling of 31191089 in words is "thirty-one million, one hundred ninety-one thousand, eighty-nine".