1666863870 has 96 divisors (see below), whose sum is σ = 4732732800. Its totient is φ = 374520384.

The previous prime is 1666863853. The next prime is 1666863871. The reversal of 1666863870 is 783686661.

It is a happy number.

It is a super-2 number, since 2×1666863870² = 5556870322222753800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666863871) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 77121 + ... + 96339.

It is an arithmetic number, because the mean of its divisors is an integer number (49299300).

Almost surely, 2^1666863870 is an apocalyptic number.

1666863870 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1666863870, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2366366400).

1666863870 is an abundant number, since it is smaller than the sum of its proper divisors (3065868930).

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

1666863870 is a wasteful number, since it uses less digits than its factorization.

1666863870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19302 (or 19295 counting only the distinct ones).

The product of its (nonzero) digits is 1741824, while the sum is 51.

The square root of 1666863870 is about 40827.2442126578. The cubic root of 1666863870 is about 1185.6778617335.

The spelling of 1666863870 in words is "one billion, six hundred sixty-six million, eight hundred sixty-three thousand, eight hundred seventy".