21207995 has 4 divisors (see below), whose sum is σ = 25449600. Its totient is φ = 16966392.

The previous prime is 21207881. The next prime is 21207997. The reversal of 21207995 is 59970212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21207995 - 2¹⁰ = 21206971 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21207997) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2120795 + ... + 2120804.

It is an arithmetic number, because the mean of its divisors is an integer number (6362400).

Almost surely, 2^21207995 is an apocalyptic number.

21207995 is a deficient number, since it is larger than the sum of its proper divisors (4241605).

21207995 is an equidigital number, since it uses as much as digits as its factorization.

21207995 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4241604.

The product of its (nonzero) digits is 11340, while the sum is 35.

The square root of 21207995 is about 4605.2138929696. The cubic root of 21207995 is about 276.8002878685.

The spelling of 21207995 in words is "twenty-one million, two hundred seven thousand, nine hundred ninety-five".