5621721 has 24 divisors (see below), whose sum is σ = 8809920. Its totient is φ = 3179232.

The previous prime is 5621687. The next prime is 5621731. The reversal of 5621721 is 1271265.

It is not a de Polignac number, because 5621721 - 2¹⁴ = 5605337 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 5621691 and 5621700.

It is not an unprimeable number, because it can be changed into a prime (5621731) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24435 + ... + 24663.

It is an arithmetic number, because the mean of its divisors is an integer number (367080).

Almost surely, 2^5621721 is an apocalyptic number.

It is an amenable number.

5621721 is a deficient number, since it is larger than the sum of its proper divisors (3188199).

5621721 is a wasteful number, since it uses less digits than its factorization.

5621721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 413 (or 406 counting only the distinct ones).

The product of its digits is 840, while the sum is 24.

The square root of 5621721 is about 2371.0168704587. The cubic root of 5621721 is about 177.8101013130.

Adding to 5621721 its reverse (1271265), we get a palindrome (6892986).

The spelling of 5621721 in words is "five million, six hundred twenty-one thousand, seven hundred twenty-one".