7875721 has 12 divisors (see below), whose sum is σ = 9261588. Its totient is φ = 6676992.

The previous prime is 7875713. The next prime is 7875727. The reversal of 7875721 is 1275787.

It can be written as a sum of positive squares in 2 ways, for example, as 3013696 + 4862025 = 1736^2 + 2205^2 .

It is not a de Polignac number, because 7875721 - 2³ = 7875713 is a prime.

It is a d-powerful number, because it can be written as 7² + 8⁷ + 7⁴ + 5⁵ + 7⁸ + 2¹³ + 1 .

It is not an unprimeable number, because it can be changed into a prime (7875727) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3925 + ... + 5581.

It is an arithmetic number, because the mean of its divisors is an integer number (771799).

Almost surely, 2^7875721 is an apocalyptic number.

It is an amenable number.

7875721 is a deficient number, since it is larger than the sum of its proper divisors (1385867).

7875721 is a wasteful number, since it uses less digits than its factorization.

7875721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1768 (or 1761 counting only the distinct ones).

The product of its digits is 27440, while the sum is 37.

The square root of 7875721 is about 2806.3715007105. The cubic root of 7875721 is about 198.9589319561.

The spelling of 7875721 in words is "seven million, eight hundred seventy-five thousand, seven hundred twenty-one".