18995381 has 2 divisors, whose sum is σ = 18995382. Its totient is φ = 18995380.

The previous prime is 18995369. The next prime is 18995399. The reversal of 18995381 is 18359981.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16564900 + 2430481 = 4070^2 + 1559^2 .

It is an emirp because it is prime and its reverse (18359981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18995381 - 2²² = 14801077 is a prime.

It is a super-2 number, since 2×18995381² = 721648998670322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18995311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9497690 + 9497691.

It is an arithmetic number, because the mean of its divisors is an integer number (9497691).

Almost surely, 2^18995381 is an apocalyptic number.

It is an amenable number.

18995381 is a deficient number, since it is larger than the sum of its proper divisors (1).

18995381 is an equidigital number, since it uses as much as digits as its factorization.

18995381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 77760, while the sum is 44.

The square root of 18995381 is about 4358.3690756979. The cubic root of 18995381 is about 266.8185397035.

The spelling of 18995381 in words is "eighteen million, nine hundred ninety-five thousand, three hundred eighty-one".