2631721 has 4 divisors (see below), whose sum is σ = 2722500. Its totient is φ = 2540944.

The previous prime is 2631701. The next prime is 2631731. The reversal of 2631721 is 1271362.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1755625 + 876096 = 1325^2 + 936^2 .

It is a cyclic number.

It is not a de Polignac number, because 2631721 - 2⁵ = 2631689 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2631692 and 2631701.

It is not an unprimeable number, because it can be changed into a prime (2631701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45346 + ... + 45403.

It is an arithmetic number, because the mean of its divisors is an integer number (680625).

2^2631721 is an apocalyptic number.

It is an amenable number.

2631721 is a deficient number, since it is larger than the sum of its proper divisors (90779).

2631721 is an equidigital number, since it uses as much as digits as its factorization.

2631721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90778.

The product of its digits is 504, while the sum is 22.

The square root of 2631721 is about 1622.2579942783. The cubic root of 2631721 is about 138.0638400976.

The spelling of 2631721 in words is "two million, six hundred thirty-one thousand, seven hundred twenty-one".