21899279 has 2 divisors, whose sum is σ = 21899280. Its totient is φ = 21899278.

The previous prime is 21899261. The next prime is 21899303. The reversal of 21899279 is 97299812.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21899279 - 2⁸ = 21899023 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 (21899219) 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, 10949639 + 10949640.

It is an arithmetic number, because the mean of its divisors is an integer number (10949640).

Almost surely, 2^21899279 is an apocalyptic number.

21899279 is a deficient number, since it is larger than the sum of its proper divisors (1).

21899279 is an equidigital number, since it uses as much as digits as its factorization.

21899279 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 163296, while the sum is 47.

The square root of 21899279 is about 4679.6665479498. Note that the first 3 decimals coincide. The cubic root of 21899279 is about 279.7756664023.

The spelling of 21899279 in words is "twenty-one million, eight hundred ninety-nine thousand, two hundred seventy-nine".