2171954578 has 16 divisors (see below), whose sum is σ = 3451301784. Its totient is φ = 1021584640.

The previous prime is 2171954567. The next prime is 2171954599. The reversal of 2171954578 is 8754591712.

It can be written as a sum of positive squares in 4 ways, for example, as 2038251609 + 133702969 = 45147^2 + 11563^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 57876 + ... + 87712.

Almost surely, 2^2171954578 is an apocalyptic number.

2171954578 is a deficient number, since it is larger than the sum of its proper divisors (1279347206).

2171954578 is a wasteful number, since it uses less digits than its factorization.

2171954578 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31997.

The product of its digits is 705600, while the sum is 49.

The square root of 2171954578 is about 46604.2334772282. The cubic root of 2171954578 is about 1295.0411833278.

The spelling of 2171954578 in words is "two billion, one hundred seventy-one million, nine hundred fifty-four thousand, five hundred seventy-eight".