21203279 has 2 divisors, whose sum is σ = 21203280. Its totient is φ = 21203278.

The previous prime is 21203249. The next prime is 21203291. The reversal of 21203279 is 97230212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21203279 - 2⁸ = 21203023 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 (21203219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601639 + 10601640.

It is an arithmetic number, because the mean of its divisors is an integer number (10601640).

Almost surely, 2^21203279 is an apocalyptic number.

21203279 is a deficient number, since it is larger than the sum of its proper divisors (1).

21203279 is an equidigital number, since it uses as much as digits as its factorization.

21203279 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 21203279 is about 4604.7018361670. The cubic root of 21203279 is about 276.7797690825.

The spelling of 21203279 in words is "twenty-one million, two hundred three thousand, two hundred seventy-nine".