18705649 has 2 divisors, whose sum is σ = 18705650. Its totient is φ = 18705648.

The previous prime is 18705637. The next prime is 18705653. The reversal of 18705649 is 94650781.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14961424 + 3744225 = 3868^2 + 1935^2 .

It is a cyclic number.

It is not a de Polignac number, because 18705649 - 2¹³ = 18697457 is a prime.

It is a super-2 number, since 2×18705649² = 699802609022402, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18705629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9352824 + 9352825.

It is an arithmetic number, because the mean of its divisors is an integer number (9352825).

Almost surely, 2^18705649 is an apocalyptic number.

It is an amenable number.

18705649 is a deficient number, since it is larger than the sum of its proper divisors (1).

18705649 is an equidigital number, since it uses as much as digits as its factorization.

18705649 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 60480, while the sum is 40.

The square root of 18705649 is about 4325.0027745656. The cubic root of 18705649 is about 265.4550103876.

The spelling of 18705649 in words is "eighteen million, seven hundred five thousand, six hundred forty-nine".