21912799 has 2 divisors, whose sum is σ = 21912800. Its totient is φ = 21912798.

The previous prime is 21912791. The next prime is 21912823. The reversal of 21912799 is 99721912.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21912799 - 2³ = 21912791 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21912791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10956399 + 10956400.

It is an arithmetic number, because the mean of its divisors is an integer number (10956400).

Almost surely, 2^21912799 is an apocalyptic number.

21912799 is a deficient number, since it is larger than the sum of its proper divisors (1).

21912799 is an equidigital number, since it uses as much as digits as its factorization.

21912799 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20412, while the sum is 40.

The square root of 21912799 is about 4681.1108724319. The cubic root of 21912799 is about 279.8332297717.

The spelling of 21912799 in words is "twenty-one million, nine hundred twelve thousand, seven hundred ninety-nine".