21020330 has 32 divisors (see below), whose sum is σ = 40835664. Its totient is φ = 7760896.

The previous prime is 21020303. The next prime is 21020339. The reversal of 21020330 is 3302012.

It can be written as a sum of positive squares in 8 ways, for example, as 12823561 + 8196769 = 3581^2 + 2863^2 .

It is not an unprimeable number, because it can be changed into a prime (21020339) 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, 7844 + ... + 10176.

Almost surely, 2^21020330 is an apocalyptic number.

21020330 is a deficient number, since it is larger than the sum of its proper divisors (19815334).

21020330 is a wasteful number, since it uses less digits than its factorization.

21020330 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2410.

The product of its (nonzero) digits is 36, while the sum is 11.

The square root of 21020330 is about 4584.7933432162. The cubic root of 21020330 is about 275.9814189689.

Adding to 21020330 its reverse (3302012), we get a palindrome (24322342).

The spelling of 21020330 in words is "twenty-one million, twenty thousand, three hundred thirty".