20988660 has 216 divisors, whose sum is σ = 76416480. Its totient is φ = 4287360.

The previous prime is 20988637. The next prime is 20988677. The reversal of 20988660 is 6688902.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 355711 + ... + 355769.

It is an arithmetic number, because the mean of its divisors is an integer number (353780).

Almost surely, 2^20988660 is an apocalyptic number.

20988660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20988660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38208240).

20988660 is an abundant number, since it is smaller than the sum of its proper divisors (55427820).

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

20988660 is a wasteful number, since it uses less digits than its factorization.

20988660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107 (or 87 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 39.

The square root of 20988660 is about 4581.3382324382. The cubic root of 20988660 is about 275.8427480613.

The spelling of 20988660 in words is "twenty million, nine hundred eighty-eight thousand, six hundred sixty".