221219621 has 4 divisors (see below), whose sum is σ = 252822432. Its totient is φ = 189616812.

The previous prime is 221219617. The next prime is 221219629. The reversal of 221219621 is 126912122.

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 not a de Polignac number, because 221219621 - 2² = 221219617 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221219629) 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, 15801395 + ... + 15801408.

It is an arithmetic number, because the mean of its divisors is an integer number (63205608).

Almost surely, 2^221219621 is an apocalyptic number.

It is an amenable number.

221219621 is a deficient number, since it is larger than the sum of its proper divisors (31602811).

221219621 is an equidigital number, since it uses as much as digits as its factorization.

221219621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31602810.

The product of its digits is 864, while the sum is 26.

The square root of 221219621 is about 14873.4535666737. The cubic root of 221219621 is about 604.7945672298.

The spelling of 221219621 in words is "two hundred twenty-one million, two hundred nineteen thousand, six hundred twenty-one".