2156500666 has 4 divisors (see below), whose sum is σ = 3234751002. Its totient is φ = 1078250332.

The previous prime is 2156500663. The next prime is 2156500667. The reversal of 2156500666 is 6660056512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 1341683641 + 814817025 = 36629^2 + 28545^2 .

It is not an unprimeable number, because it can be changed into a prime (2156500663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 539125165 + ... + 539125168.

Almost surely, 2^2156500666 is an apocalyptic number.

2156500666 is a deficient number, since it is larger than the sum of its proper divisors (1078250336).

2156500666 is a wasteful number, since it uses less digits than its factorization.

2156500666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1078250335.

The product of its (nonzero) digits is 64800, while the sum is 37.

The square root of 2156500666 is about 46438.1380548359. The cubic root of 2156500666 is about 1291.9623731402.

The spelling of 2156500666 in words is "two billion, one hundred fifty-six million, five hundred thousand, six hundred sixty-six".