20992720 has 80 divisors (see below), whose sum is σ = 58746240. Its totient is φ = 6815232.

The previous prime is 20992711. The next prime is 20992747. The reversal of 20992720 is 2729902.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9654 + ... + 11626.

It is an arithmetic number, because the mean of its divisors is an integer number (734328).

Almost surely, 2^20992720 is an apocalyptic number.

20992720 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 20992720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29373120).

20992720 is an abundant number, since it is smaller than the sum of its proper divisors (37753520).

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

20992720 is a wasteful number, since it uses less digits than its factorization.

20992720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2012 (or 2006 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 31.

The square root of 20992720 is about 4581.7813129830. The cubic root of 20992720 is about 275.8605330518.

It can be divided in two parts, 20992 and 720, that added together give a palindrome (21712).

The spelling of 20992720 in words is "twenty million, nine hundred ninety-two thousand, seven hundred twenty".