221400022421 has 6 divisors (see below), whose sum is σ = 233665952022. Its totient is φ = 209747389320.

The previous prime is 221400022397. The next prime is 221400022439. The reversal of 221400022421 is 124220004122.

It can be written as a sum of positive squares in only one way, i.e., 209568021796 + 11832000625 = 457786^2 + 108775^2 .

It is not a de Polignac number, because 221400022421 - 2¹⁸ = 221399760277 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221400022393 and 221400022402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221400022621) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 306647870 + ... + 306648591.

It is an arithmetic number, because the mean of its divisors is an integer number (38944325337).

Almost surely, 2^221400022421 is an apocalyptic number.

It is an amenable number.

221400022421 is a deficient number, since it is larger than the sum of its proper divisors (12265929601).

221400022421 is an equidigital number, since it uses as much as digits as its factorization.

221400022421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 613296499 (or 613296480 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 20.

Adding to 221400022421 its reverse (124220004122), we get a palindrome (345620026543).

The spelling of 221400022421 in words is "two hundred twenty-one billion, four hundred million, twenty-two thousand, four hundred twenty-one".