221638073 has 4 divisors (see below), whose sum is σ = 224759808. Its totient is φ = 218516340.

The previous prime is 221638069. The next prime is 221638091. The reversal of 221638073 is 370836122.

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 221638073 - 2² = 221638069 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221638973) 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, 1560761 + ... + 1560902.

It is an arithmetic number, because the mean of its divisors is an integer number (56189952).

Almost surely, 2^221638073 is an apocalyptic number.

It is an amenable number.

221638073 is a deficient number, since it is larger than the sum of its proper divisors (3121735).

221638073 is an equidigital number, since it uses as much as digits as its factorization.

221638073 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3121734.

The product of its (nonzero) digits is 12096, while the sum is 32.

The square root of 221638073 is about 14887.5139966349. The cubic root of 221638073 is about 605.1756637641.

The spelling of 221638073 in words is "two hundred twenty-one million, six hundred thirty-eight thousand, seventy-three".