20744720 has 20 divisors (see below), whose sum is σ = 48231660. Its totient is φ = 8297856.

The previous prime is 20744699. The next prime is 20744723. The reversal of 20744720 is 2744702.

It can be written as a sum of positive squares in 2 ways, for example, as 4999696 + 15745024 = 2236^2 + 3968^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a self number, because there is not a number n which added to its sum of digits gives 20744720.

It is not an unprimeable number, because it can be changed into a prime (20744723) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 129575 + ... + 129734.

It is an arithmetic number, because the mean of its divisors is an integer number (2411583).

Almost surely, 2^20744720 is an apocalyptic number.

20744720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20744720 is an abundant number, since it is smaller than the sum of its proper divisors (27486940).

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

20744720 is a wasteful number, since it uses less digits than its factorization.

20744720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 259322 (or 259316 counting only the distinct ones).

The product of its (nonzero) digits is 3136, while the sum is 26.

The square root of 20744720 is about 4554.6371974066. The cubic root of 20744720 is about 274.7699232641.

The spelling of 20744720 in words is "twenty million, seven hundred forty-four thousand, seven hundred twenty".