21901799 has 2 divisors, whose sum is σ = 21901800. Its totient is φ = 21901798.

The previous prime is 21901793. The next prime is 21901811. The reversal of 21901799 is 99710912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21901799 - 2⁴ = 21901783 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 (21901793) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10950899 + 10950900.

It is an arithmetic number, because the mean of its divisors is an integer number (10950900).

Almost surely, 2^21901799 is an apocalyptic number.

21901799 is a deficient number, since it is larger than the sum of its proper divisors (1).

21901799 is an equidigital number, since it uses as much as digits as its factorization.

21901799 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10206, while the sum is 38.

The square root of 21901799 is about 4679.9357901578. The cubic root of 21901799 is about 279.7863974654.

The spelling of 21901799 in words is "twenty-one million, nine hundred one thousand, seven hundred ninety-nine".