21030980 has 12 divisors (see below), whose sum is σ = 44165100. Its totient is φ = 8412384.

The previous prime is 21030979. The next prime is 21031009. The reversal of 21030980 is 8903012.

It can be written as a sum of positive squares in 2 ways, for example, as 6270016 + 14760964 = 2504^2 + 3842^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 525755 + ... + 525794.

It is an arithmetic number, because the mean of its divisors is an integer number (3680425).

Almost surely, 2^21030980 is an apocalyptic number.

21030980 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21030980 is an abundant number, since it is smaller than the sum of its proper divisors (23134120).

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

21030980 is a wasteful number, since it uses less digits than its factorization.

21030980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1051558 (or 1051556 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 21030980 is about 4585.9546443461. The cubic root of 21030980 is about 276.0280199796.

Adding to 21030980 its reverse (8903012), we get a palindrome (29933992).

The spelling of 21030980 in words is "twenty-one million, thirty thousand, nine hundred eighty".