1661666166 has 24 divisors (see below), whose sum is σ = 3789765720. Its totient is φ = 524736576.

The previous prime is 1661666159. The next prime is 1661666197. The reversal of 1661666166 is 6616661661.

It is a super-2 number, since 2×1661666166² = 5522268894458279112, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2428995 + ... + 2429678.

It is an arithmetic number, because the mean of its divisors is an integer number (157906905).

Almost surely, 2^1661666166 is an apocalyptic number.

1661666166 is an abundant number, since it is smaller than the sum of its proper divisors (2128099554).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1661666166 is a wasteful number, since it uses less digits than its factorization.

1661666166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4858700 (or 4858697 counting only the distinct ones).

The product of its digits is 279936, while the sum is 45.

The square root of 1661666166 is about 40763.5396647543. The cubic root of 1661666166 is about 1184.4441638248. Note that the first 3 decimals are identical.

The spelling of 1661666166 in words is "one billion, six hundred sixty-one million, six hundred sixty-six thousand, one hundred sixty-six".