3072721 has 4 divisors (see below), whose sum is σ = 3082852. Its totient is φ = 3062592.

The previous prime is 3072709. The next prime is 3072749. The reversal of 3072721 is 1272703.

3072721 = 1239² + 1240².

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1272703 = 479 ⋅2657.

It can be written as a sum of positive squares in 2 ways, for example, as 1535121 + 1537600 = 1239^2 + 1240^2 .

It is a cyclic number.

It is not a de Polignac number, because 3072721 - 2¹⁷ = 2941649 is a prime.

It is a super-2 number, since 2×3072721² = 18883228687682, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 3072692 and 3072701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3072701) 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, 4596 + ... + 5221.

It is an arithmetic number, because the mean of its divisors is an integer number (770713).

Almost surely, 2^3072721 is an apocalyptic number.

3072721 is the 1240-th centered square number.

It is an amenable number.

3072721 is a deficient number, since it is larger than the sum of its proper divisors (10131).

3072721 is an equidigital number, since it uses as much as digits as its factorization.

3072721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10130.

The product of its (nonzero) digits is 588, while the sum is 22.

The square root of 3072721 is about 1752.9178531808. The cubic root of 3072721 is about 145.3810193143.

The spelling of 3072721 in words is "three million, seventy-two thousand, seven hundred twenty-one".