21480813 has 6 divisors (see below), whose sum is σ = 31027854. Its totient is φ = 14320536.

The previous prime is 21480791. The next prime is 21480817. The reversal of 21480813 is 31808412.

It can be written as a sum of positive squares in only one way, i.e., 20958084 + 522729 = 4578^2 + 723^2 .

It is not a de Polignac number, because 21480813 - 2⁶ = 21480749 is a prime.

It is a super-2 number, since 2×21480813² = 922850654281938, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21480817) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1193370 + ... + 1193387.

It is an arithmetic number, because the mean of its divisors is an integer number (5171309).

Almost surely, 2^21480813 is an apocalyptic number.

It is an amenable number.

21480813 is a deficient number, since it is larger than the sum of its proper divisors (9547041).

21480813 is a wasteful number, since it uses less digits than its factorization.

21480813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2386763 (or 2386760 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 21480813 is about 4634.7397985216. The cubic root of 21480813 is about 277.9821469480.

The spelling of 21480813 in words is "twenty-one million, four hundred eighty thousand, eight hundred thirteen".