2171651979 has 16 divisors (see below), whose sum is σ = 3423294720. Its totient is φ = 1198152480.

The previous prime is 2171651971. The next prime is 2171651983. The reversal of 2171651979 is 9791561712.

It is not a de Polignac number, because 2171651979 - 2³ = 2171651971 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2171651971) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1782357 + ... + 1783574.

It is an arithmetic number, because the mean of its divisors is an integer number (213955920).

Almost surely, 2^2171651979 is an apocalyptic number.

2171651979 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

2171651979 is a deficient number, since it is larger than the sum of its proper divisors (1251642741).

2171651979 is a wasteful number, since it uses less digits than its factorization.

2171651979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3565970.

The product of its digits is 238140, while the sum is 48.

The square root of 2171651979 is about 46600.9868886915. The cubic root of 2171651979 is about 1294.9810383672.

The spelling of 2171651979 in words is "two billion, one hundred seventy-one million, six hundred fifty-one thousand, nine hundred seventy-nine".