18738961 has 2 divisors, whose sum is σ = 18738962. Its totient is φ = 18738960.

The previous prime is 18738943. The next prime is 18738971. The reversal of 18738961 is 16983781.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18147600 + 591361 = 4260^2 + 769^2 .

It is a cyclic number.

It is not a de Polignac number, because 18738961 - 2¹⁷ = 18607889 is a prime.

It is a super-2 number, since 2×18738961² = 702297318719042, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18738971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9369480 + 9369481.

It is an arithmetic number, because the mean of its divisors is an integer number (9369481).

Almost surely, 2^18738961 is an apocalyptic number.

It is an amenable number.

18738961 is a deficient number, since it is larger than the sum of its proper divisors (1).

18738961 is an equidigital number, since it uses as much as digits as its factorization.

18738961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 72576, while the sum is 43.

The square root of 18738961 is about 4328.8521573276. The cubic root of 18738961 is about 265.6124956697.

The spelling of 18738961 in words is "eighteen million, seven hundred thirty-eight thousand, nine hundred sixty-one".