221000100021 has 12 divisors (see below), whose sum is σ = 319226686272. Its totient is φ = 147331406376.

The previous prime is 221000100001. The next prime is 221000100053. The reversal of 221000100021 is 120001000122.

It is not a de Polignac number, because 221000100021 - 2⁷ = 221000099893 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 221000099976 and 221000100012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221000100001) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 887860 + ... + 1109186.

It is an arithmetic number, because the mean of its divisors is an integer number (26602223856).

Almost surely, 2^221000100021 is an apocalyptic number.

It is an amenable number.

221000100021 is a deficient number, since it is larger than the sum of its proper divisors (98226586251).

221000100021 is a wasteful number, since it uses less digits than its factorization.

221000100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332280 (or 332277 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 221000100021 its reverse (120001000122), we get a palindrome (341001100143).

The spelling of 221000100021 in words is "two hundred twenty-one billion, one hundred thousand, twenty-one".