1866165660 has 72 divisors (see below), whose sum is σ = 5855915520. Its totient is φ = 480482688.

The previous prime is 1866165641. The next prime is 1866165661. The reversal of 1866165660 is 665616681.

1866165660 is a `hidden beast` number, since 1 + 86 + 6 + 1 + 6 + 566 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1866165661) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 173532 + ... + 183971.

It is an arithmetic number, because the mean of its divisors is an integer number (81332160).

Almost surely, 2^1866165660 is an apocalyptic number.

1866165660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1866165660 is an abundant number, since it is smaller than the sum of its proper divisors (3989749860).

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

1866165660 is a wasteful number, since it uses less digits than its factorization.

1866165660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 357547 (or 357542 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 45.

The square root of 1866165660 is about 43199.1395747647. The cubic root of 1866165660 is about 1231.1663337034.

The spelling of 1866165660 in words is "one billion, eight hundred sixty-six million, one hundred sixty-five thousand, six hundred sixty".