42171720 has 64 divisors (see below), whose sum is σ = 127854720. Its totient is φ = 11126784.

The previous prime is 42171707. The next prime is 42171721. The reversal of 42171720 is 2717124.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (42171721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9829 + ... + 13451.

It is an arithmetic number, because the mean of its divisors is an integer number (1997730).

Almost surely, 2^42171720 is an apocalyptic number.

42171720 is a gapful number since it is divisible by the number (40) 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 42171720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (63927360).

42171720 is an abundant number, since it is smaller than the sum of its proper divisors (85683000).

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

42171720 is a wasteful number, since it uses less digits than its factorization.

42171720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3734 (or 3730 counting only the distinct ones).

The product of its (nonzero) digits is 784, while the sum is 24.

The square root of 42171720 is about 6493.9756698035. The cubic root of 42171720 is about 348.0757530952.

Adding to 42171720 its reverse (2717124), we get a palindrome (44888844).

The spelling of 42171720 in words is "forty-two million, one hundred seventy-one thousand, seven hundred twenty".