21265899 has 8 divisors (see below), whose sum is σ = 28378512. Its totient is φ = 14165280.

The previous prime is 21265897. The next prime is 21265913. The reversal of 21265899 is 99856212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21265899 - 2¹ = 21265897 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21265899.

It is not an unprimeable number, because it can be changed into a prime (21265891) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2677 + ... + 7049.

It is an arithmetic number, because the mean of its divisors is an integer number (3547314).

Almost surely, 2^21265899 is an apocalyptic number.

21265899 is a deficient number, since it is larger than the sum of its proper divisors (7112613).

21265899 is a wasteful number, since it uses less digits than its factorization.

21265899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5997.

The product of its digits is 77760, while the sum is 42.

The square root of 21265899 is about 4611.4963948810. The cubic root of 21265899 is about 277.0519740692.

The spelling of 21265899 in words is "twenty-one million, two hundred sixty-five thousand, eight hundred ninety-nine".