21496809 has 8 divisors (see below), whose sum is σ = 30171040. Its totient is φ = 13576896.

The previous prime is 21496763. The next prime is 21496817. The reversal of 21496809 is 90869412.

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

It is not a de Polignac number, because 21496809 - 2¹⁷ = 21365737 is a prime.

It is a super-2 number, since 2×21496809² = 924225594364962, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21496819) 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, 188512 + ... + 188625.

It is an arithmetic number, because the mean of its divisors is an integer number (3771380).

Almost surely, 2^21496809 is an apocalyptic number.

It is an amenable number.

21496809 is a deficient number, since it is larger than the sum of its proper divisors (8674231).

21496809 is a wasteful number, since it uses less digits than its factorization.

21496809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 377159.

The product of its (nonzero) digits is 31104, while the sum is 39.

The square root of 21496809 is about 4636.4651406001. The cubic root of 21496809 is about 278.0511309778.

The spelling of 21496809 in words is "twenty-one million, four hundred ninety-six thousand, eight hundred nine".