21080420 has 24 divisors (see below), whose sum is σ = 46194624. Its totient is φ = 8065376.

The previous prime is 21080401. The next prime is 21080447. The reversal of 21080420 is 2408012.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22454 + ... + 23373.

It is an arithmetic number, because the mean of its divisors is an integer number (1924776).

Almost surely, 2^21080420 is an apocalyptic number.

21080420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21080420 is an abundant number, since it is smaller than the sum of its proper divisors (25114204).

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

21080420 is a wasteful number, since it uses less digits than its factorization.

21080420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45859 (or 45857 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

The square root of 21080420 is about 4591.3418517902. The cubic root of 21080420 is about 276.2441478937.

Adding to 21080420 its reverse (2408012), we get a palindrome (23488432).

The spelling of 21080420 in words is "twenty-one million, eighty thousand, four hundred twenty".