2640172205 has 18 divisors (see below), whose sum is σ = 3484076778. Its totient is φ = 1919206080.

The previous prime is 2640172201. The next prime is 2640172217. The reversal of 2640172205 is 5022710462.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 1240589284 + 1399582921 = 35222^2 + 37411^2 .

It is not a de Polignac number, because 2640172205 - 2² = 2640172201 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2640172201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1262801 + ... + 1264889.

It is an arithmetic number, because the mean of its divisors is an integer number (193559821).

Almost surely, 2^2640172205 is an apocalyptic number.

It is an amenable number.

2640172205 is a deficient number, since it is larger than the sum of its proper divisors (843904573).

2640172205 is an frugal number, since it uses more digits than its factorization.

2640172205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4205 (or 2105 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 29.

The square root of 2640172205 is about 51382.6060549677. The cubic root of 2640172205 is about 1382.1146960921.

Adding to 2640172205 its reverse (5022710462), we get a palindrome (7662882667).

The spelling of 2640172205 in words is "two billion, six hundred forty million, one hundred seventy-two thousand, two hundred five".