21020313 has 16 divisors (see below), whose sum is σ = 29768256. Its totient is φ = 13148160.

The previous prime is 21020303. The next prime is 21020339. The reversal of 21020313 is 31302012.

It is a happy number.

It is not a de Polignac number, because 21020313 - 2⁵ = 21020281 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21020303) 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, 32370 + ... + 33012.

It is an arithmetic number, because the mean of its divisors is an integer number (1860516).

Almost surely, 2^21020313 is an apocalyptic number.

It is an amenable number.

21020313 is a deficient number, since it is larger than the sum of its proper divisors (8747943).

21020313 is a wasteful number, since it uses less digits than its factorization.

21020313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1304.

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 21020313 is about 4584.7914892610. The cubic root of 21020313 is about 275.9813445698.

Adding to 21020313 its reverse (31302012), we get a palindrome (52322325).

The spelling of 21020313 in words is "twenty-one million, twenty thousand, three hundred thirteen".