20999760 has 80 divisors (see below), whose sum is σ = 68942016. Its totient is φ = 5269504.

The previous prime is 20999729. The next prime is 20999767. The reversal of 20999760 is 6799902.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20999767) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1507 + ... + 6653.

Almost surely, 2^20999760 is an apocalyptic number.

20999760 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 20999760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34471008).

20999760 is an abundant number, since it is smaller than the sum of its proper divisors (47942256).

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

20999760 is a wasteful number, since it uses less digits than its factorization.

20999760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5180 (or 5174 counting only the distinct ones).

The product of its (nonzero) digits is 61236, while the sum is 42.

The square root of 20999760 is about 4582.5495087342. The cubic root of 20999760 is about 275.8913666154.

The spelling of 20999760 in words is "twenty million, nine hundred ninety-nine thousand, seven hundred sixty".