66173940 has 144 divisors (see below), whose sum is σ = 237444480. Its totient is φ = 14595840.

The previous prime is 66173929. The next prime is 66173951. The reversal of 66173940 is 4937166.

66173940 is a `hidden beast` number, since 6 + 617 + 39 + 4 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (66173929) and next prime (66173951).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 66173895 and 66173904.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 35635 + ... + 37445.

It is an arithmetic number, because the mean of its divisors is an integer number (1648920).

Almost surely, 2^66173940 is an apocalyptic number.

66173940 is a gapful number since it is divisible by the number (60) 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 66173940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118722240).

66173940 is an abundant number, since it is smaller than the sum of its proper divisors (171270540).

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

66173940 is a wasteful number, since it uses less digits than its factorization.

66173940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1862 (or 1857 counting only the distinct ones).

The product of its (nonzero) digits is 27216, while the sum is 36.

The square root of 66173940 is about 8134.7366275744. The cubic root of 66173940 is about 404.4787074539.

The spelling of 66173940 in words is "sixty-six million, one hundred seventy-three thousand, nine hundred forty".