20256720 has 80 divisors (see below), whose sum is σ = 68513472. Its totient is φ = 4910080.

The previous prime is 20256689. The next prime is 20256737. The reversal of 20256720 is 2765202.

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

It is a Harshad number since it is a multiple of its sum of digits (24).

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, 1197 + ... + 6476.

Almost surely, 2^20256720 is an apocalyptic number.

20256720 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 20256720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34256736).

20256720 is an abundant number, since it is smaller than the sum of its proper divisors (48256752).

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

20256720 is a wasteful number, since it uses less digits than its factorization.

20256720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7700 (or 7694 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 24.

The square root of 20256720 is about 4500.7466047313. The cubic root of 20256720 is about 272.5982363319.

The spelling of 20256720 in words is "twenty million, two hundred fifty-six thousand, seven hundred twenty".