221402421 has 24 divisors (see below), whose sum is σ = 338694720. Its totient is φ = 138977856.

The previous prime is 221402387. The next prime is 221402437. The reversal of 221402421 is 124204122.

221402421 is a `hidden beast` number, since 221 + 402 + 42 + 1 = 666.

221402421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 221402421 - 2⁹ = 221401909 is a prime.

It is a super-2 number, since 2×221402421² = 98038064049322482, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 221402394 and 221402403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221402471) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24681 + ... + 32433.

It is an arithmetic number, because the mean of its divisors is an integer number (14112280).

Almost surely, 2^221402421 is an apocalyptic number.

It is an amenable number.

221402421 is a deficient number, since it is larger than the sum of its proper divisors (117292299).

221402421 is a wasteful number, since it uses less digits than its factorization.

221402421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7945 (or 7942 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 221402421 is about 14879.5974743943. The cubic root of 221402421 is about 604.9611076244.

Adding to 221402421 its reverse (124204122), we get a palindrome (345606543).

The spelling of 221402421 in words is "two hundred twenty-one million, four hundred two thousand, four hundred twenty-one".