20791680 has 384 divisors, whose sum is σ = 87907680. Its totient is φ = 4128768.

The previous prime is 20791657. The next prime is 20791691. The reversal of 20791680 is 8619702.

It is a tau number, because it is divible by the number of its divisors (384).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1223032 + ... + 1223048.

Almost surely, 2^20791680 is an apocalyptic number.

20791680 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 20791680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43953840).

20791680 is an abundant number, since it is smaller than the sum of its proper divisors (67116000).

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

20791680 is a wasteful number, since it uses less digits than its factorization.

20791680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66 (or 47 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 33.

The square root of 20791680 is about 4559.7894688242. The cubic root of 20791680 is about 274.9771000215.

The spelling of 20791680 in words is "twenty million, seven hundred ninety-one thousand, six hundred eighty".