21854891556 has 135 divisors (see below), whose sum is σ = 58800424683. Its totient is φ = 7078291920.

The previous prime is 21854891549. The next prime is 21854891573. The reversal of 21854891556 is 65519845812.

The square root of 21854891556 is 147834.

It is a perfect power (a square), and thus also a powerful number.

21854891556 is a `hidden beast` number, since 2 + 1 + 8 + 5 + 4 + 89 + 1 + 556 = 666.

It is a super-2 number, since 2×21854891556² (a number of 21 digits) contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 114423421 + ... + 114423611.

Almost surely, 2^21854891556 is an apocalyptic number.

21854891556 is the 147834-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21854891556

21854891556 is an abundant number, since it is smaller than the sum of its proper divisors (36945533127).

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

21854891556 is an equidigital number, since it uses as much as digits as its factorization.

21854891556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 484 (or 239 counting only the distinct ones).

The product of its digits is 3456000, while the sum is 54.

The spelling of 21854891556 in words is "twenty-one billion, eight hundred fifty-four million, eight hundred ninety-one thousand, five hundred fifty-six".