20278656 has 96 divisors (see below), whose sum is σ = 60465600. Its totient is φ = 6515712.

The previous prime is 20278651. The next prime is 20278673. The reversal of 20278656 is 65687202.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×20278656² = 822447778332672, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 20278656.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20278651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 33105 + ... + 33711.

It is an arithmetic number, because the mean of its divisors is an integer number (629850).

Almost surely, 2^20278656 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 20278656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30232800).

20278656 is an abundant number, since it is smaller than the sum of its proper divisors (40186944).

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

20278656 is a wasteful number, since it uses less digits than its factorization.

20278656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 656 (or 641 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The square root of 20278656 is about 4503.1828743679. The cubic root of 20278656 is about 272.6965997019.

The spelling of 20278656 in words is "twenty million, two hundred seventy-eight thousand, six hundred fifty-six".