18392981 has 2 divisors, whose sum is σ = 18392982. Its totient is φ = 18392980.

The previous prime is 18392947. The next prime is 18392999. The reversal of 18392981 is 18929381.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15928081 + 2464900 = 3991^2 + 1570^2 .

It is a cyclic number.

It is not a de Polignac number, because 18392981 - 2¹⁴ = 18376597 is a prime.

It is a super-2 number, since 2×18392981² = 676603500132722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18392081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9196490 + 9196491.

It is an arithmetic number, because the mean of its divisors is an integer number (9196491).

Almost surely, 2^18392981 is an apocalyptic number.

It is an amenable number.

18392981 is a deficient number, since it is larger than the sum of its proper divisors (1).

18392981 is an equidigital number, since it uses as much as digits as its factorization.

18392981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31104, while the sum is 41.

The square root of 18392981 is about 4288.7038834594. The cubic root of 18392981 is about 263.9676508036.

The spelling of 18392981 in words is "eighteen million, three hundred ninety-two thousand, nine hundred eighty-one".