1666863220 has 24 divisors (see below), whose sum is σ = 3818632608. Its totient is φ = 606132000.

The previous prime is 1666863173. The next prime is 1666863251. The reversal of 1666863220 is 223686661.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3788106 + ... + 3788545.

It is an arithmetic number, because the mean of its divisors is an integer number (159109692).

Almost surely, 2^1666863220 is an apocalyptic number.

1666863220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1666863220 is an abundant number, since it is smaller than the sum of its proper divisors (2151769388).

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

1666863220 is a wasteful number, since it uses less digits than its factorization.

1666863220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7576671 (or 7576669 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 40.

The square root of 1666863220 is about 40827.2362522863. The cubic root of 1666863220 is about 1185.6777076136.

The spelling of 1666863220 in words is "one billion, six hundred sixty-six million, eight hundred sixty-three thousand, two hundred twenty".