21227399 has 2 divisors, whose sum is σ = 21227400. Its totient is φ = 21227398.

The previous prime is 21227387. The next prime is 21227419. The reversal of 21227399 is 99372212.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21227399 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21227309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10613699 + 10613700.

It is an arithmetic number, because the mean of its divisors is an integer number (10613700).

Almost surely, 2^21227399 is an apocalyptic number.

21227399 is a deficient number, since it is larger than the sum of its proper divisors (1).

21227399 is an equidigital number, since it uses as much as digits as its factorization.

21227399 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13608, while the sum is 35.

The square root of 21227399 is about 4607.3201538421. The cubic root of 21227399 is about 276.8846805007.

The spelling of 21227399 in words is "twenty-one million, two hundred twenty-seven thousand, three hundred ninety-nine".