2664721 has 2 divisors, whose sum is σ = 2664722. Its totient is φ = 2664720.

The previous prime is 2664709. The next prime is 2664763. The reversal of 2664721 is 1274662.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1918225 + 746496 = 1385^2 + 864^2 .

It is a cyclic number.

It is not a de Polignac number, because 2664721 - 2⁵ = 2664689 is a prime.

2664721 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 2664721.

It is not a weakly prime, because it can be changed into another prime (2664521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1332360 + 1332361.

It is an arithmetic number, because the mean of its divisors is an integer number (1332361).

2^2664721 is an apocalyptic number.

It is an amenable number.

2664721 is a deficient number, since it is larger than the sum of its proper divisors (1).

2664721 is an equidigital number, since it uses as much as digits as its factorization.

2664721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4032, while the sum is 28.

The square root of 2664721 is about 1632.3973168319. The cubic root of 2664721 is about 138.6385204163.

The spelling of 2664721 in words is "two million, six hundred sixty-four thousand, seven hundred twenty-one".