7285721 has 4 divisors (see below), whose sum is σ = 7669200. Its totient is φ = 6902244.

The previous prime is 7285711. The next prime is 7285723. The reversal of 7285721 is 1275827.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1275827 = 7 ⋅182261.

It is a de Polignac number, because none of the positive numbers 2^k-7285721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7285723) 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, 191711 + ... + 191748.

It is an arithmetic number, because the mean of its divisors is an integer number (1917300).

Almost surely, 2^7285721 is an apocalyptic number.

It is an amenable number.

7285721 is a deficient number, since it is larger than the sum of its proper divisors (383479).

7285721 is a wasteful number, since it uses less digits than its factorization.

7285721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 383478.

The product of its digits is 7840, while the sum is 32.

The square root of 7285721 is about 2699.2074762789. The cubic root of 7285721 is about 193.8611771220.

The spelling of 7285721 in words is "seven million, two hundred eighty-five thousand, seven hundred twenty-one".