18701615531 has 2 divisors, whose sum is σ = 18701615532. Its totient is φ = 18701615530.

The previous prime is 18701615509. The next prime is 18701615533. The reversal of 18701615531 is 13551610781.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18701615531 - 2⁶ = 18701615467 is a prime.

It is a super-2 number, since 2×18701615531² (a number of 21 digits) contains 22 as substring.

Together with 18701615533, 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 (18701615533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9350807765 + 9350807766.

It is an arithmetic number, because the mean of its divisors is an integer number (9350807766).

Almost surely, 2^18701615531 is an apocalyptic number.

18701615531 is a deficient number, since it is larger than the sum of its proper divisors (1).

18701615531 is an equidigital number, since it uses as much as digits as its factorization.

18701615531 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25200, while the sum is 38.

The spelling of 18701615531 in words is "eighteen billion, seven hundred one million, six hundred fifteen thousand, five hundred thirty-one".