2021663556 has 96 divisors (see below), whose sum is σ = 5814950400. Its totient is φ = 602220960.

The previous prime is 2021663549. The next prime is 2021663563. The reversal of 2021663556 is 6553661202.

It is a happy number.

2021663556 is a `hidden beast` number, since 2 + 0 + 2 + 16 + 635 + 5 + 6 = 666.

It is an interprime number because it is at equal distance from previous prime (2021663549) and next prime (2021663563).

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 2021663556.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 55671 + ... + 84513.

It is an arithmetic number, because the mean of its divisors is an integer number (60572400).

Almost surely, 2^2021663556 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 2021663556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2907475200).

2021663556 is an abundant number, since it is smaller than the sum of its proper divisors (3793286844).

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

2021663556 is a wasteful number, since it uses less digits than its factorization.

2021663556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28926 (or 28918 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 36.

The square root of 2021663556 is about 44962.9131173682. The cubic root of 2021663556 is about 1264.4537849201.

The spelling of 2021663556 in words is "two billion, twenty-one million, six hundred sixty-three thousand, five hundred fifty-six".