139097531 has 2 divisors, whose sum is σ = 139097532. Its totient is φ = 139097530.

The previous prime is 139097509. The next prime is 139097533. The reversal of 139097531 is 135790931.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 139097531 - 2¹⁴ = 139081147 is a prime.

It is a super-2 number, since 2×139097531² = 38696246260591922, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 139097533, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (139097533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69548765 + 69548766.

It is an arithmetic number, because the mean of its divisors is an integer number (69548766).

Almost surely, 2^139097531 is an apocalyptic number.

139097531 is a deficient number, since it is larger than the sum of its proper divisors (1).

139097531 is an equidigital number, since it uses as much as digits as its factorization.

139097531 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25515, while the sum is 38.

The square root of 139097531 is about 11793.9616329713. The cubic root of 139097531 is about 518.1312744017.

The spelling of 139097531 in words is "one hundred thirty-nine million, ninety-seven thousand, five hundred thirty-one".