221662021 has 4 divisors (see below), whose sum is σ = 253328032. Its totient is φ = 189996012.

The previous prime is 221662019. The next prime is 221662039. The reversal of 221662021 is 120266122.

221662021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 221662021 - 2¹ = 221662019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221661983 and 221662001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221662081) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15832995 + ... + 15833008.

It is an arithmetic number, because the mean of its divisors is an integer number (63332008).

Almost surely, 2^221662021 is an apocalyptic number.

It is an amenable number.

221662021 is a deficient number, since it is larger than the sum of its proper divisors (31666011).

221662021 is an equidigital number, since it uses as much as digits as its factorization.

221662021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31666010.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 221662021 is about 14888.3182730623. The cubic root of 221662021 is about 605.1974593949.

The spelling of 221662021 in words is "two hundred twenty-one million, six hundred sixty-two thousand, twenty-one".