20621980 has 24 divisors (see below), whose sum is σ = 43405488. Its totient is φ = 8229888.

The previous prime is 20621977. The next prime is 20621981. The reversal of 20621980 is 8912602.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20621981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10647 + ... + 12433.

It is an arithmetic number, because the mean of its divisors is an integer number (1808562).

Almost surely, 2^20621980 is an apocalyptic number.

20621980 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20621980 is an abundant number, since it is smaller than the sum of its proper divisors (22783508).

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

20621980 is a wasteful number, since it uses less digits than its factorization.

20621980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2373 (or 2371 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 20621980 is about 4541.1430279171. The cubic root of 20621980 is about 274.2269418242.

The spelling of 20621980 in words is "twenty million, six hundred twenty-one thousand, nine hundred eighty".