7721213 has 6 divisors (see below), whose sum is σ = 8202426. Its totient is φ = 7266752.

The previous prime is 7721191. The next prime is 7721249. The reversal of 7721213 is 3121277.

It can be written as a sum of positive squares in 3 ways, for example, as 1951609 + 5769604 = 1397^2 + 2402^2 .

It is not a de Polignac number, because 7721213 - 2⁶ = 7721149 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 (7721293) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 13070 + ... + 13647.

It is an arithmetic number, because the mean of its divisors is an integer number (1367071).

Almost surely, 2^7721213 is an apocalyptic number.

It is an amenable number.

7721213 is a deficient number, since it is larger than the sum of its proper divisors (481213).

7721213 is a wasteful number, since it uses less digits than its factorization.

7721213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26751 (or 26734 counting only the distinct ones).

The product of its digits is 588, while the sum is 23.

The square root of 7721213 is about 2778.7070734426. The cubic root of 7721213 is about 197.6492531995.

The spelling of 7721213 in words is "seven million, seven hundred twenty-one thousand, two hundred thirteen".