21204867 has 16 divisors (see below), whose sum is σ = 28730240. Its totient is φ = 13910400.

The previous prime is 21204863. The next prime is 21204871. The reversal of 21204867 is 76840212.

It is an interprime number because it is at equal distance from previous prime (21204863) and next prime (21204871).

It is not a de Polignac number, because 21204867 - 2² = 21204863 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21204863) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 87867 + ... + 88107.

It is an arithmetic number, because the mean of its divisors is an integer number (1795640).

Almost surely, 2^21204867 is an apocalyptic number.

21204867 is a deficient number, since it is larger than the sum of its proper divisors (7525373).

21204867 is a wasteful number, since it uses less digits than its factorization.

21204867 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 594.

The product of its (nonzero) digits is 5376, while the sum is 30.

The square root of 21204867 is about 4604.8742653845. The cubic root of 21204867 is about 276.7866786318.

The spelling of 21204867 in words is "twenty-one million, two hundred four thousand, eight hundred sixty-seven".