221555100420 has 48 divisors (see below), whose sum is σ = 689282536320. Its totient is φ = 59081359968.

The previous prime is 221555100353. The next prime is 221555100451. The reversal of 221555100420 is 24001555122.

221555100420 is a `hidden beast` number, since 2 + 2 + 1 + 555 + 100 + 4 + 2 + 0 = 666.

It is a super-3 number, since 3×221555100420³ (a number of 35 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 205143072 + ... + 205144151.

It is an arithmetic number, because the mean of its divisors is an integer number (14360052840).

Almost surely, 2^221555100420 is an apocalyptic number.

221555100420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221555100420 is an abundant number, since it is smaller than the sum of its proper divisors (467727435900).

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

221555100420 is a wasteful number, since it uses less digits than its factorization.

221555100420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 410287241 (or 410287233 counting only the distinct ones).

The product of its (nonzero) digits is 4000, while the sum is 27.

Adding to 221555100420 its reverse (24001555122), we get a palindrome (245556655542).

The spelling of 221555100420 in words is "two hundred twenty-one billion, five hundred fifty-five million, one hundred thousand, four hundred twenty".