221152021 has 4 divisors (see below), whose sum is σ = 223299232. Its totient is φ = 219004812.

The previous prime is 221152013. The next prime is 221152027. The reversal of 221152021 is 120251122.

It is a happy number.

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 221152021 - 2³ = 221152013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221151986 and 221152004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221152027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1073451 + ... + 1073656.

It is an arithmetic number, because the mean of its divisors is an integer number (55824808).

Almost surely, 2^221152021 is an apocalyptic number.

It is an amenable number.

221152021 is a deficient number, since it is larger than the sum of its proper divisors (2147211).

221152021 is a wasteful number, since it uses less digits than its factorization.

221152021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2147210.

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 221152021 is about 14871.1808878784. The cubic root of 221152021 is about 604.7329568451.

The spelling of 221152021 in words is "two hundred twenty-one million, one hundred fifty-two thousand, twenty-one".