20280656 has 40 divisors (see below), whose sum is σ = 43226400. Its totient is φ = 9141120.

The previous prime is 20280607. The next prime is 20280661. The reversal of 20280656 is 65608202.

It is a super-2 number, since 2×20280656² = 822610015580672, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24050 + ... + 24878.

It is an arithmetic number, because the mean of its divisors is an integer number (1080660).

Almost surely, 2^20280656 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20280656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21613200).

20280656 is an abundant number, since it is smaller than the sum of its proper divisors (22945744).

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

20280656 is a wasteful number, since it uses less digits than its factorization.

20280656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 987 (or 981 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 29.

The square root of 20280656 is about 4503.4049340471. The cubic root of 20280656 is about 272.7055643866.

Adding to 20280656 its reverse (65608202), we get a palindrome (85888858).

The spelling of 20280656 in words is "twenty million, two hundred eighty thousand, six hundred fifty-six".