2157747866 has 8 divisors (see below), whose sum is σ = 3240832980. Its totient is φ = 1077470208.

The previous prime is 2157747859. The next prime is 2157747883. The reversal of 2157747866 is 6687477512.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 1770642241 + 387105625 = 42079^2 + 19675^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 699941 + ... + 703016.

Almost surely, 2^2157747866 is an apocalyptic number.

2157747866 is a deficient number, since it is larger than the sum of its proper divisors (1083085114).

2157747866 is a wasteful number, since it uses less digits than its factorization.

2157747866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1403728.

The product of its digits is 3951360, while the sum is 53.

The square root of 2157747866 is about 46451.5647314490. The cubic root of 2157747866 is about 1292.2113915247.

The spelling of 2157747866 in words is "two billion, one hundred fifty-seven million, seven hundred forty-seven thousand, eight hundred sixty-six".