2171959649 has 4 divisors (see below), whose sum is σ = 2196363780. Its totient is φ = 2147555520.

The previous prime is 2171959639. The next prime is 2171959697. The reversal of 2171959649 is 9469591712.

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 1553542225 + 618417424 = 39415^2 + 24868^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2171959649 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 2171959649.

It is not an unprimeable number, because it can be changed into a prime (2171959619) 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, 12201932 + ... + 12202109.

It is an arithmetic number, because the mean of its divisors is an integer number (549090945).

Almost surely, 2^2171959649 is an apocalyptic number.

It is an amenable number.

2171959649 is a deficient number, since it is larger than the sum of its proper divisors (24404131).

2171959649 is an equidigital number, since it uses as much as digits as its factorization.

2171959649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24404130.

The product of its digits is 1224720, while the sum is 53.

The square root of 2171959649 is about 46604.2878821252. The cubic root of 2171959649 is about 1295.0421911986.

The spelling of 2171959649 in words is "two billion, one hundred seventy-one million, nine hundred fifty-nine thousand, six hundred forty-nine".