18651131 has 2 divisors, whose sum is σ = 18651132. Its totient is φ = 18651130.

The previous prime is 18651109. The next prime is 18651133. The reversal of 18651131 is 13115681.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18651131 is a prime.

It is a super-2 number, since 2×18651131² = 695729375158322, which contains 22 as substring.

Together with 18651133, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18651131.

It is not a weakly prime, because it can be changed into another prime (18651133) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9325565 + 9325566.

It is an arithmetic number, because the mean of its divisors is an integer number (9325566).

Almost surely, 2^18651131 is an apocalyptic number.

18651131 is a deficient number, since it is larger than the sum of its proper divisors (1).

18651131 is an equidigital number, since it uses as much as digits as its factorization.

18651131 is an evil number, because the sum of its binary digits is even.

The product of its digits is 720, while the sum is 26.

The square root of 18651131 is about 4318.6955206405. The cubic root of 18651131 is about 265.1968680694.

The spelling of 18651131 in words is "eighteen million, six hundred fifty-one thousand, one hundred thirty-one".