1666911690 has 64 divisors (see below), whose sum is σ = 4456581120. Its totient is φ = 443361600.

The previous prime is 1666911689. The next prime is 1666911691. The reversal of 1666911690 is 961196661.

1666911690 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (1666911689) and next prime (1666911691).

It is a super-2 number, since 2×1666911690² = 5557189164517312200, which contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (1666911691) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 99415 + ... + 114965.

It is an arithmetic number, because the mean of its divisors is an integer number (69634080).

Almost surely, 2^1666911690 is an apocalyptic number.

1666911690 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 1666911690, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2228290560).

1666911690 is an abundant number, since it is smaller than the sum of its proper divisors (2789669430).

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

1666911690 is a wasteful number, since it uses less digits than its factorization.

1666911690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15964 (or 15958 counting only the distinct ones).

The product of its (nonzero) digits is 104976, while the sum is 45.

The square root of 1666911690 is about 40827.8298468091. The cubic root of 1666911690 is about 1185.6892001066.

The spelling of 1666911690 in words is "one billion, six hundred sixty-six million, nine hundred eleven thousand, six hundred ninety".