42188721 has 8 divisors (see below), whose sum is σ = 59212320. Its totient is φ = 26645472.

The previous prime is 42188711. The next prime is 42188749. The reversal of 42188721 is 12788124.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 42188721 - 2⁷ = 42188593 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (42188711) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 370020 + ... + 370133.

It is an arithmetic number, because the mean of its divisors is an integer number (7401540).

Almost surely, 2^42188721 is an apocalyptic number.

It is an amenable number.

42188721 is a deficient number, since it is larger than the sum of its proper divisors (17023599).

42188721 is a wasteful number, since it uses less digits than its factorization.

42188721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 740175.

The product of its digits is 7168, while the sum is 33.

The square root of 42188721 is about 6495.2845203270. The cubic root of 42188721 is about 348.1225209359.

The spelling of 42188721 in words is "forty-two million, one hundred eighty-eight thousand, seven hundred twenty-one".