166637640 has 128 divisors (see below), whose sum is σ = 553109760. Its totient is φ = 39896064.

The previous prime is 166637609. The next prime is 166637659. The reversal of 166637640 is 46736661.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 56277 + ... + 59163.

It is an arithmetic number, because the mean of its divisors is an integer number (4321170).

Almost surely, 2^166637640 is an apocalyptic number.

166637640 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 166637640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (276554880).

166637640 is an abundant number, since it is smaller than the sum of its proper divisors (386472120).

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

166637640 is a wasteful number, since it uses less digits than its factorization.

166637640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2951 (or 2947 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 39.

The square root of 166637640 is about 12908.8202404403. The cubic root of 166637640 is about 550.2892583137.

The spelling of 166637640 in words is "one hundred sixty-six million, six hundred thirty-seven thousand, six hundred forty".