2157824666 has 16 divisors (see below), whose sum is σ = 3285311400. Its totient is φ = 1062759168.

The previous prime is 2157824659. The next prime is 2157824677. The reversal of 2157824666 is 6664287512.

It can be written as a sum of positive squares in 4 ways, for example, as 2156209225 + 1615441 = 46435^2 + 1271^2 .

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 2157824666.

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, 108980 + ... + 127248.

Almost surely, 2^2157824666 is an apocalyptic number.

2157824666 is a deficient number, since it is larger than the sum of its proper divisors (1127486734).

2157824666 is a wasteful number, since it uses less digits than its factorization.

2157824666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19153.

The product of its digits is 967680, while the sum is 47.

The square root of 2157824666 is about 46452.3913916173. The cubic root of 2157824666 is about 1292.2267224258.

The spelling of 2157824666 in words is "two billion, one hundred fifty-seven million, eight hundred twenty-four thousand, six hundred sixty-six".