18926021 has 2 divisors, whose sum is σ = 18926022. Its totient is φ = 18926020.

The previous prime is 18925979. The next prime is 18926023. The reversal of 18926021 is 12062981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13912900 + 5013121 = 3730^2 + 2239^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18926021 is a prime.

Together with 18926023, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18926023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9463010 + 9463011.

It is an arithmetic number, because the mean of its divisors is an integer number (9463011).

Almost surely, 2^18926021 is an apocalyptic number.

It is an amenable number.

18926021 is a deficient number, since it is larger than the sum of its proper divisors (1).

18926021 is an equidigital number, since it uses as much as digits as its factorization.

18926021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 18926021 is about 4350.4046938187. The cubic root of 18926021 is about 266.4933886449.

The spelling of 18926021 in words is "eighteen million, nine hundred twenty-six thousand, twenty-one".