21020260 has 48 divisors (see below), whose sum is σ = 45505152. Its totient is φ = 8153600.

The previous prime is 21020239. The next prime is 21020267. The reversal of 21020260 is 6202012.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21020260.

It is not an unprimeable number, because it can be changed into a prime (21020267) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 160395 + ... + 160525.

It is an arithmetic number, because the mean of its divisors is an integer number (948024).

Almost surely, 2^21020260 is an apocalyptic number.

21020260 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21020260 is an abundant number, since it is smaller than the sum of its proper divisors (24484892).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21020260 is a wasteful number, since it uses less digits than its factorization.

21020260 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 324 (or 322 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 21020260 is about 4584.7857092780. The cubic root of 21020260 is about 275.9811126192.

Adding to 21020260 its reverse (6202012), we get a palindrome (27222272).

The spelling of 21020260 in words is "twenty-one million, twenty thousand, two hundred sixty".