18857749 has 2 divisors, whose sum is σ = 18857750. Its totient is φ = 18857748.

The previous prime is 18857737. The next prime is 18857759. The reversal of 18857749 is 94775881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12830724 + 6027025 = 3582^2 + 2455^2 .

It is an emirp because it is prime and its reverse (94775881) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18857749 - 2⁵ = 18857717 is a prime.

It is a super-2 number, since 2×18857749² = 711229394694002, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18857759) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9428874 + 9428875.

It is an arithmetic number, because the mean of its divisors is an integer number (9428875).

Almost surely, 2^18857749 is an apocalyptic number.

It is an amenable number.

18857749 is a deficient number, since it is larger than the sum of its proper divisors (1).

18857749 is an equidigital number, since it uses as much as digits as its factorization.

18857749 is an evil number, because the sum of its binary digits is even.

The product of its digits is 564480, while the sum is 49.

The square root of 18857749 is about 4342.5509783997. The cubic root of 18857749 is about 266.1725612551.

The spelling of 18857749 in words is "eighteen million, eight hundred fifty-seven thousand, seven hundred forty-nine".