42640917 has 8 divisors (see below), whose sum is σ = 62023200. Its totient is φ = 25842960.

The previous prime is 42640901. The next prime is 42640931. The reversal of 42640917 is 71904624.

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 42640917 - 2⁴ = 42640901 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 a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 1292149 = 42640917 / (4 + 2 + 6 + 4 + 0 + 9 + 1 + 7).

It is a plaindrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42640937) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 646042 + ... + 646107.

It is an arithmetic number, because the mean of its divisors is an integer number (7752900).

Almost surely, 2^42640917 is an apocalyptic number.

It is an amenable number.

42640917 is a deficient number, since it is larger than the sum of its proper divisors (19382283).

42640917 is a wasteful number, since it uses less digits than its factorization.

42640917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1292163.

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 42640917 is about 6530.0013016844. The cubic root of 42640917 is about 349.3618767305.

It can be divided in two parts, 426409 and 17, that added together give a triangular number (426426 = T₉₂₃).

The spelling of 42640917 in words is "forty-two million, six hundred forty thousand, nine hundred seventeen".