2645721 has 12 divisors (see below), whose sum is σ = 4115748. Its totient is φ = 1628064.

The previous prime is 2645717. The next prime is 2645723. The reversal of 2645721 is 1275462.

It can be written as a sum of positive squares in 2 ways, for example, as 741321 + 1904400 = 861^2 + 1380^2 .

It is not a de Polignac number, because 2645721 - 2² = 2645717 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2645723) 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, 11190 + ... + 11423.

It is an arithmetic number, because the mean of its divisors is an integer number (342979).

2^2645721 is an apocalyptic number.

It is an amenable number.

2645721 is a deficient number, since it is larger than the sum of its proper divisors (1470027).

2645721 is a wasteful number, since it uses less digits than its factorization.

2645721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22632 (or 22629 counting only the distinct ones).

The product of its digits is 3360, while the sum is 27.

The square root of 2645721 is about 1626.5672442294. The cubic root of 2645721 is about 138.3082272465.

The spelling of 2645721 in words is "two million, six hundred forty-five thousand, seven hundred twenty-one".