21209795 has 32 divisors (see below), whose sum is σ = 29652480. Its totient is φ = 14446080.

The previous prime is 21209791. The next prime is 21209801. The reversal of 21209795 is 59790212.

It is not a de Polignac number, because 21209795 - 2² = 21209791 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21209791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 36860 + ... + 37430.

It is an arithmetic number, because the mean of its divisors is an integer number (926640).

Almost surely, 2^21209795 is an apocalyptic number.

21209795 is a deficient number, since it is larger than the sum of its proper divisors (8442685).

21209795 is a wasteful number, since it uses less digits than its factorization.

21209795 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 635.

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

The square root of 21209795 is about 4605.4093194851. The cubic root of 21209795 is about 276.8081186641.

The spelling of 21209795 in words is "twenty-one million, two hundred nine thousand, seven hundred ninety-five".