1866978868 has 6 divisors (see below), whose sum is σ = 3267213026. Its totient is φ = 933489432.

The previous prime is 1866978863. The next prime is 1866978887. The reversal of 1866978868 is 8688796681.

It can be written as a sum of positive squares in only one way, i.e., 1834237584 + 32741284 = 42828^2 + 5722^2 .

It is a super-2 number, since 2×1866978868² = 6971220187117122848, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1866978863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 233372355 + ... + 233372362.

Almost surely, 2^1866978868 is an apocalyptic number.

It is an amenable number.

1866978868 is a deficient number, since it is larger than the sum of its proper divisors (1400234158).

1866978868 is a wasteful number, since it uses less digits than its factorization.

1866978868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 466744721 (or 466744719 counting only the distinct ones).

The product of its digits is 55738368, while the sum is 67.

The square root of 1866978868 is about 43208.5508666977. The cubic root of 1866978868 is about 1231.3451404300.

The spelling of 1866978868 in words is "one billion, eight hundred sixty-six million, nine hundred seventy-eight thousand, eight hundred sixty-eight".