6553721 has 8 divisors (see below), whose sum is σ = 7035624. Its totient is φ = 6082560.

The previous prime is 6553663. The next prime is 6553733. The reversal of 6553721 is 1273556.

It can be written as a sum of positive squares in 4 ways, for example, as 846400 + 5707321 = 920^2 + 2389^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6553721 - 2¹⁰ = 6552697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6553021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1400 + ... + 3881.

It is an arithmetic number, because the mean of its divisors is an integer number (879453).

Almost surely, 2^6553721 is an apocalyptic number.

It is an amenable number.

6553721 is a deficient number, since it is larger than the sum of its proper divisors (481903).

6553721 is a wasteful number, since it uses less digits than its factorization.

6553721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5371.

The product of its digits is 6300, while the sum is 29.

The square root of 6553721 is about 2560.0236327034. The cubic root of 6553721 is about 187.1382869513.

The spelling of 6553721 in words is "six million, five hundred fifty-three thousand, seven hundred twenty-one".