21620260 has 24 divisors (see below), whose sum is σ = 48074040. Its totient is φ = 8139264.

The previous prime is 21620251. The next prime is 21620267. The reversal of 21620260 is 6202612.

It can be written as a sum of positive squares in 4 ways, for example, as 9634816 + 11985444 = 3104^2 + 3462^2 .

It is not an unprimeable number, because it can be changed into a prime (21620267) 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 7 ways as a sum of consecutive naturals, for example, 31455 + ... + 32134.

It is an arithmetic number, because the mean of its divisors is an integer number (2003085).

Almost surely, 2^21620260 is an apocalyptic number.

21620260 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21620260 is an abundant number, since it is smaller than the sum of its proper divisors (26453780).

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

21620260 is a wasteful number, since it uses less digits than its factorization.

21620260 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63615 (or 63613 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 21620260 is about 4649.7591335466. The cubic root of 21620260 is about 278.5823755756.

Adding to 21620260 its reverse (6202612), we get a palindrome (27822872).

The spelling of 21620260 in words is "twenty-one million, six hundred twenty thousand, two hundred sixty".