1866661880 has 32 divisors (see below), whose sum is σ = 4447049040. Its totient is φ = 702743040.

The previous prime is 1866661861. The next prime is 1866661891. The reversal of 1866661880 is 881666681.

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, 1371866 + ... + 1373225.

Almost surely, 2^1866661880 is an apocalyptic number.

1866661880 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1866661880 is an abundant number, since it is smaller than the sum of its proper divisors (2580387160).

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

1866661880 is a wasteful number, since it uses less digits than its factorization.

1866661880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2745119 (or 2745115 counting only the distinct ones).

The product of its (nonzero) digits is 663552, while the sum is 50.

The square root of 1866661880 is about 43204.8825944476. The cubic root of 1866661880 is about 1231.2754478494.

The spelling of 1866661880 in words is "one billion, eight hundred sixty-six million, six hundred sixty-one thousand, eight hundred eighty".