7916221 has 4 divisors (see below), whose sum is σ = 7969500. Its totient is φ = 7862944.

The previous prime is 7916213. The next prime is 7916263. The reversal of 7916221 is 1226197.

7916221 = 1989² + 1990².

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3960100 + 3956121 = 1990^2 + 1989^2 .

It is a cyclic number.

It is not a de Polignac number, because 7916221 - 2³ = 7916213 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 7916221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4916221) 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, 26416 + ... + 26713.

It is an arithmetic number, because the mean of its divisors is an integer number (1992375).

Almost surely, 2^7916221 is an apocalyptic number.

7916221 is the 1990-th centered square number.

It is an amenable number.

7916221 is a deficient number, since it is larger than the sum of its proper divisors (53279).

7916221 is a wasteful number, since it uses less digits than its factorization.

7916221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53278.

The product of its digits is 1512, while the sum is 28.

The square root of 7916221 is about 2813.5779711961. The cubic root of 7916221 is about 199.2993902625.

The spelling of 7916221 in words is "seven million, nine hundred sixteen thousand, two hundred twenty-one".