21727899 has 16 divisors (see below), whose sum is σ = 32672640. Its totient is φ = 14267880.

The previous prime is 21727897. The next prime is 21727913. The reversal of 21727899 is 99872712.

It is not a de Polignac number, because 21727899 - 2¹ = 21727897 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21727897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4197 + ... + 7814.

It is an arithmetic number, because the mean of its divisors is an integer number (2042040).

Almost surely, 2^21727899 is an apocalyptic number.

21727899 is a deficient number, since it is larger than the sum of its proper divisors (10944741).

21727899 is a wasteful number, since it uses less digits than its factorization.

21727899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12087 (or 12081 counting only the distinct ones).

The product of its digits is 127008, while the sum is 45.

The square root of 21727899 is about 4661.3194483966. The cubic root of 21727899 is about 279.0439287981.

The spelling of 21727899 in words is "twenty-one million, seven hundred twenty-seven thousand, eight hundred ninety-nine".