5623721 has 4 divisors (see below), whose sum is σ = 5639172. Its totient is φ = 5608272.

The previous prime is 5623649. The next prime is 5623727. The reversal of 5623721 is 1273265.

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 1297321 + 4326400 = 1139^2 + 2080^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-5623721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (5623727) 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, 7166 + ... + 7911.

It is an arithmetic number, because the mean of its divisors is an integer number (1409793).

Almost surely, 2^5623721 is an apocalyptic number.

It is an amenable number.

5623721 is a deficient number, since it is larger than the sum of its proper divisors (15451).

5623721 is a wasteful number, since it uses less digits than its factorization.

5623721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15450.

The product of its digits is 2520, while the sum is 26.

The square root of 5623721 is about 2371.4385929220. The cubic root of 5623721 is about 177.8311848945.

Adding to 5623721 its reverse (1273265), we get a palindrome (6896986).

The spelling of 5623721 in words is "five million, six hundred twenty-three thousand, seven hundred twenty-one".