7451721 has 6 divisors (see below), whose sum is σ = 10763610. Its totient is φ = 4967808.

The previous prime is 7451713. The next prime is 7451723. The reversal of 7451721 is 1271547.

It can be written as a sum of positive squares in only one way, i.e., 5588496 + 1863225 = 2364^2 + 1365^2 .

It is not a de Polignac number, because 7451721 - 2³ = 7451713 is a prime.

It is not an unprimeable number, because it can be changed into a prime (7451723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 413976 + ... + 413993.

It is an arithmetic number, because the mean of its divisors is an integer number (1793935).

Almost surely, 2^7451721 is an apocalyptic number.

It is an amenable number.

7451721 is a deficient number, since it is larger than the sum of its proper divisors (3311889).

7451721 is a wasteful number, since it uses less digits than its factorization.

7451721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 827975 (or 827972 counting only the distinct ones).

The product of its digits is 1960, while the sum is 27.

The square root of 7451721 is about 2729.7840573936. The cubic root of 7451721 is about 195.3224644858.

The spelling of 7451721 in words is "seven million, four hundred fifty-one thousand, seven hundred twenty-one".