2640150721 has 4 divisors (see below), whose sum is σ = 2843239252. Its totient is φ = 2437062192.

The previous prime is 2640150713. The next prime is 2640150769. The reversal of 2640150721 is 1270510462.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 796650625 + 1843500096 = 28225^2 + 42936^2 .

It is a cyclic number.

It is not a de Polignac number, because 2640150721 - 2³ = 2640150713 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2640150721.

It is not an unprimeable number, because it can be changed into a prime (2640130721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 101544246 + ... + 101544271.

It is an arithmetic number, because the mean of its divisors is an integer number (710809813).

Almost surely, 2^2640150721 is an apocalyptic number.

It is an amenable number.

2640150721 is a deficient number, since it is larger than the sum of its proper divisors (203088531).

2640150721 is a wasteful number, since it uses less digits than its factorization.

2640150721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 203088530.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 2640150721 is about 51382.3969954692. The cubic root of 2640150721 is about 1382.1109471659.

The spelling of 2640150721 in words is "two billion, six hundred forty million, one hundred fifty thousand, seven hundred twenty-one".