247664531 has 2 divisors, whose sum is σ = 247664532. Its totient is φ = 247664530.

The previous prime is 247664509. The next prime is 247664533. The reversal of 247664531 is 135466742.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-247664531 is a prime.

It is a super-2 number, since 2×247664531² = 122675439830899922, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 247664533, 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 (247664533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 123832265 + 123832266.

It is an arithmetic number, because the mean of its divisors is an integer number (123832266).

Almost surely, 2^247664531 is an apocalyptic number.

247664531 is a deficient number, since it is larger than the sum of its proper divisors (1).

247664531 is an equidigital number, since it uses as much as digits as its factorization.

247664531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 120960, while the sum is 38.

The square root of 247664531 is about 15737.3609922375. The cubic root of 247664531 is about 627.9927134468.

The spelling of 247664531 in words is "two hundred forty-seven million, six hundred sixty-four thousand, five hundred thirty-one".