1666379520 has 288 divisors, whose sum is σ = 6369921600. Its totient is φ = 410075136.

The previous prime is 1666379513. The next prime is 1666379521. The reversal of 1666379520 is 259736661.

It is a tau number, because it is divible by the number of its divisors (288).

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 (1666379521) 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, 447426 + ... + 451134.

Almost surely, 2^1666379520 is an apocalyptic number.

1666379520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1666379520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3184960800).

1666379520 is an abundant number, since it is smaller than the sum of its proper divisors (4703542080).

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

1666379520 is a wasteful number, since it uses less digits than its factorization.

1666379520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3752 (or 3732 counting only the distinct ones).

The product of its (nonzero) digits is 408240, while the sum is 45.

The square root of 1666379520 is about 40821.3120808237. The cubic root of 1666379520 is about 1185.5630075822.

The spelling of 1666379520 in words is "one billion, six hundred sixty-six million, three hundred seventy-nine thousand, five hundred twenty".