7920221 has 8 divisors (see below), whose sum is σ = 8217600. Its totient is φ = 7625520.

The previous prime is 7920217. The next prime is 7920229. The reversal of 7920221 is 1220297.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 7920221 - 2² = 7920217 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7920229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6875 + ... + 7943.

It is an arithmetic number, because the mean of its divisors is an integer number (1027200).

Almost surely, 2^7920221 is an apocalyptic number.

It is an amenable number.

7920221 is a deficient number, since it is larger than the sum of its proper divisors (297379).

7920221 is a wasteful number, since it uses less digits than its factorization.

7920221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1339.

The product of its (nonzero) digits is 504, while the sum is 23.

The square root of 7920221 is about 2814.2887200854. The cubic root of 7920221 is about 199.3329527130.

The spelling of 7920221 in words is "seven million, nine hundred twenty thousand, two hundred twenty-one".