21228573555 has 240 divisors, whose sum is σ = 46981509120. Its totient is φ = 9169723584.

The previous prime is 21228573493. The next prime is 21228573581. The reversal of 21228573555 is 55537582212.

21228573555 is a `hidden beast` number, since 2 + 1 + 2 + 28 + 5 + 73 + 555 = 666.

It is not a de Polignac number, because 21228573555 - 2⁸ = 21228573299 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 21228573555.

It is an unprimeable number.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 55426894 + ... + 55427276.

It is an arithmetic number, because the mean of its divisors is an integer number (195756288).

Almost surely, 2^21228573555 is an apocalyptic number.

21228573555 is an abundant number, since it is smaller than the sum of its proper divisors (25752935565).

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

21228573555 is an frugal number, since it uses more digits than its factorization.

21228573555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 450 (or 417 counting only the distinct ones).

The product of its digits is 840000, while the sum is 45.

The spelling of 21228573555 in words is "twenty-one billion, two hundred twenty-eight million, five hundred seventy-three thousand, five hundred fifty-five".