21526784856 has 96 divisors (see below), whose sum is σ = 61602100560. Its totient is φ = 7040172672.

The previous prime is 21526784831. The next prime is 21526784869. The reversal of 21526784856 is 65848762512.

21526784856 is a `hidden beast` number, since 2 + 1 + 526 + 78 + 48 + 5 + 6 = 666.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1435 + ... + 207498.

Almost surely, 2^21526784856 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 21526784856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30801050280).

21526784856 is an abundant number, since it is smaller than the sum of its proper divisors (40075315704).

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

21526784856 is a wasteful number, since it uses less digits than its factorization.

21526784856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 209007 (or 208991 counting only the distinct ones).

The product of its digits is 6451200, while the sum is 54.

The spelling of 21526784856 in words is "twenty-one billion, five hundred twenty-six million, seven hundred eighty-four thousand, eight hundred fifty-six".