18396981 has 24 divisors (see below), whose sum is σ = 27645696. Its totient is φ = 11776320.

The previous prime is 18396979. The next prime is 18397003. The reversal of 18396981 is 18969381.

It is not a de Polignac number, because 18396981 - 2¹ = 18396979 is a prime.

It is a super-2 number, since 2×18396981² = 676897819828722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18392981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 64866 + ... + 65148.

It is an arithmetic number, because the mean of its divisors is an integer number (1151904).

Almost surely, 2^18396981 is an apocalyptic number.

It is an amenable number.

18396981 is a deficient number, since it is larger than the sum of its proper divisors (9248715).

18396981 is a wasteful number, since it uses less digits than its factorization.

18396981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 553 (or 550 counting only the distinct ones).

The product of its digits is 93312, while the sum is 45.

The square root of 18396981 is about 4289.1701994675. The cubic root of 18396981 is about 263.9867848068.

The spelling of 18396981 in words is "eighteen million, three hundred ninety-six thousand, nine hundred eighty-one".