18902921 has 2 divisors, whose sum is σ = 18902922. Its totient is φ = 18902920.

The previous prime is 18902903. The next prime is 18902959. The reversal of 18902921 is 12920981.

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., 18361225 + 541696 = 4285^2 + 736^2 .

It is a cyclic number.

It is not a de Polignac number, because 18902921 - 2¹⁴ = 18886537 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18962921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9451460 + 9451461.

It is an arithmetic number, because the mean of its divisors is an integer number (9451461).

Almost surely, 2^18902921 is an apocalyptic number.

It is an amenable number.

18902921 is a deficient number, since it is larger than the sum of its proper divisors (1).

18902921 is an equidigital number, since it uses as much as digits as its factorization.

18902921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 18902921 is about 4347.7489577941. The cubic root of 18902921 is about 266.3849223957.

The spelling of 18902921 in words is "eighteen million, nine hundred two thousand, nine hundred twenty-one".