18821279 has 2 divisors, whose sum is σ = 18821280. Its totient is φ = 18821278.

The previous prime is 18821239. The next prime is 18821311. The reversal of 18821279 is 97212881.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18821279 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18821219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9410639 + 9410640.

It is an arithmetic number, because the mean of its divisors is an integer number (9410640).

Almost surely, 2^18821279 is an apocalyptic number.

18821279 is a deficient number, since it is larger than the sum of its proper divisors (1).

18821279 is an equidigital number, since it uses as much as digits as its factorization.

18821279 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16128, while the sum is 38.

The square root of 18821279 is about 4338.3498014798. The cubic root of 18821279 is about 266.0008621149. Note that the first 3 decimals are identical.

The spelling of 18821279 in words is "eighteen million, eight hundred twenty-one thousand, two hundred seventy-nine".