21300813 has 40 divisors (see below), whose sum is σ = 34848000. Its totient is φ = 12908160.

The previous prime is 21300791. The next prime is 21300833. The reversal of 21300813 is 31800312.

It is not a de Polignac number, because 21300813 - 2⁶ = 21300749 is a prime.

21300813 is a modest number, since divided by 813 gives 213 as remainder.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21300833) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 42438 + ... + 42936.

It is an arithmetic number, because the mean of its divisors is an integer number (871200).

Almost surely, 2^21300813 is an apocalyptic number.

It is an amenable number.

21300813 is a deficient number, since it is larger than the sum of its proper divisors (13547187).

21300813 is a wasteful number, since it uses less digits than its factorization.

21300813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 559 (or 550 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 21300813 is about 4615.2803815153. The cubic root of 21300813 is about 277.2035109467.

The spelling of 21300813 in words is "twenty-one million, three hundred thousand, eight hundred thirteen".