18220402531 has 2 divisors, whose sum is σ = 18220402532. Its totient is φ = 18220402530.

The previous prime is 18220402481. The next prime is 18220402537. The reversal of 18220402531 is 13520402281.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18220402531 - 2⁹ = 18220402019 is a prime.

It is a super-2 number, since 2×18220402531² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 18220402531.

It is not a weakly prime, because it can be changed into another prime (18220402537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9110201265 + 9110201266.

It is an arithmetic number, because the mean of its divisors is an integer number (9110201266).

Almost surely, 2^18220402531 is an apocalyptic number.

18220402531 is a deficient number, since it is larger than the sum of its proper divisors (1).

18220402531 is an equidigital number, since it uses as much as digits as its factorization.

18220402531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3840, while the sum is 28.

The spelling of 18220402531 in words is "eighteen billion, two hundred twenty million, four hundred two thousand, five hundred thirty-one".