5561721 has 12 divisors (see below), whose sum is σ = 8764080. Its totient is φ = 3370680.

The previous prime is 5561719. The next prime is 5561779. The reversal of 5561721 is 1271655.

5561721 = T₂₅ + T₂₆ + ... + T₃₂₁.

It is not a de Polignac number, because 5561721 - 2¹ = 5561719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (5561701) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27991 + ... + 28188.

It is an arithmetic number, because the mean of its divisors is an integer number (730340).

Almost surely, 2^5561721 is an apocalyptic number.

It is an amenable number.

5561721 is a deficient number, since it is larger than the sum of its proper divisors (3202359).

5561721 is a wasteful number, since it uses less digits than its factorization.

5561721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56196 (or 56193 counting only the distinct ones).

The product of its digits is 2100, while the sum is 27.

The square root of 5561721 is about 2358.3301295620. The cubic root of 5561721 is about 177.1752549324.

It can be divided in two parts, 55 and 61721, that added together give a triangular number (61776 = T₃₅₁).

The spelling of 5561721 in words is "five million, five hundred sixty-one thousand, seven hundred twenty-one".