7977221 has 16 divisors (see below), whose sum is σ = 9419904. Its totient is φ = 6614784.

The previous prime is 7977217. The next prime is 7977227. The reversal of 7977221 is 1227797.

It is a cyclic number.

It is not a de Polignac number, because 7977221 - 2² = 7977217 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7977227) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34121 + ... + 34353.

It is an arithmetic number, because the mean of its divisors is an integer number (588744).

Almost surely, 2^7977221 is an apocalyptic number.

7977221 is the 1631-st octagonal number.

It is an amenable number.

7977221 is a deficient number, since it is larger than the sum of its proper divisors (1442683).

7977221 is a wasteful number, since it uses less digits than its factorization.

7977221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 380.

The product of its digits is 12348, while the sum is 35.

The square root of 7977221 is about 2824.3974578660. The cubic root of 7977221 is about 199.8099945468.

The spelling of 7977221 in words is "seven million, nine hundred seventy-seven thousand, two hundred twenty-one".