42009819 has 4 divisors (see below), whose sum is σ = 56013096. Its totient is φ = 28006544.

The previous prime is 42009809. The next prime is 42009823. The reversal of 42009819 is 91890024.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 42009819 - 2⁹ = 42009307 is a prime.

It is a super-2 number, since 2×42009819² = 3529649784825522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 42009819.

It is not an unprimeable number, because it can be changed into a prime (42009809) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7001634 + ... + 7001639.

It is an arithmetic number, because the mean of its divisors is an integer number (14003274).

Almost surely, 2^42009819 is an apocalyptic number.

42009819 is a deficient number, since it is larger than the sum of its proper divisors (14003277).

42009819 is a wasteful number, since it uses less digits than its factorization.

42009819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14003276.

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 42009819 is about 6481.4982064334. The cubic root of 42009819 is about 347.6297505570.

The spelling of 42009819 in words is "forty-two million, nine thousand, eight hundred nineteen".