1666122890 has 16 divisors (see below), whose sum is σ = 3048186600. Its totient is φ = 655523520.

The previous prime is 1666122883. The next prime is 1666122911. The reversal of 1666122890 is 982216661.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 687121369 + 979001521 = 26213^2 + 31289^2 .

It is a Curzon number.

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 1365065 + ... + 1366284.

Almost surely, 2^1666122890 is an apocalyptic number.

1666122890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1666122890 is a deficient number, since it is larger than the sum of its proper divisors (1382063710).

1666122890 is a wasteful number, since it uses less digits than its factorization.

1666122890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2731417.

The product of its (nonzero) digits is 62208, while the sum is 41.

The square root of 1666122890 is about 40818.1686262380. The cubic root of 1666122890 is about 1185.5021437652.

The spelling of 1666122890 in words is "one billion, six hundred sixty-six million, one hundred twenty-two thousand, eight hundred ninety".