18862721 has 2 divisors, whose sum is σ = 18862722. Its totient is φ = 18862720.

The previous prime is 18862693. The next prime is 18862733. The reversal of 18862721 is 12726881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10660225 + 8202496 = 3265^2 + 2864^2 .

It is a cyclic number.

It is not a de Polignac number, because 18862721 - 2¹⁸ = 18600577 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18862021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9431360 + 9431361.

It is an arithmetic number, because the mean of its divisors is an integer number (9431361).

Almost surely, 2^18862721 is an apocalyptic number.

It is an amenable number.

18862721 is a deficient number, since it is larger than the sum of its proper divisors (1).

18862721 is an equidigital number, since it uses as much as digits as its factorization.

18862721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10752, while the sum is 35.

The square root of 18862721 is about 4343.1234152393. The cubic root of 18862721 is about 266.1959520583.

The spelling of 18862721 in words is "eighteen million, eight hundred sixty-two thousand, seven hundred twenty-one".