18996381 has 6 divisors (see below), whose sum is σ = 27439230. Its totient is φ = 12664248.

The previous prime is 18996377. The next prime is 18996401. The reversal of 18996381 is 18369981.

18996381 is a `hidden beast` number, since 1 + 8 + 9 + 9 + 638 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 18844281 + 152100 = 4341^2 + 390^2 .

It is not a de Polignac number, because 18996381 - 2² = 18996377 is a prime.

It is a super-2 number, since 2×18996381² = 721724982194322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18996311) 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 5 ways as a sum of consecutive naturals, for example, 1055346 + ... + 1055363.

It is an arithmetic number, because the mean of its divisors is an integer number (4573205).

Almost surely, 2^18996381 is an apocalyptic number.

It is an amenable number.

18996381 is a deficient number, since it is larger than the sum of its proper divisors (8442849).

18996381 is a wasteful number, since it uses less digits than its factorization.

18996381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2110715 (or 2110712 counting only the distinct ones).

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

The square root of 18996381 is about 4358.4837960006. The cubic root of 18996381 is about 266.8232217866.

The spelling of 18996381 in words is "eighteen million, nine hundred ninety-six thousand, three hundred eighty-one".