42878779 has 4 divisors (see below), whose sum is σ = 42987184. Its totient is φ = 42770376.

The previous prime is 42878767. The next prime is 42878807. The reversal of 42878779 is 97787824.

It is a happy number.

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 42878779 - 2¹⁹ = 42354491 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42872779) 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, 53607 + ... + 54400.

It is an arithmetic number, because the mean of its divisors is an integer number (10746796).

Almost surely, 2^42878779 is an apocalyptic number.

42878779 is a deficient number, since it is larger than the sum of its proper divisors (108405).

42878779 is a wasteful number, since it uses less digits than its factorization.

42878779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108404.

The product of its digits is 1580544, while the sum is 52.

The square root of 42878779 is about 6548.1889862770. The cubic root of 42878779 is about 350.0102826911.

The spelling of 42878779 in words is "forty-two million, eight hundred seventy-eight thousand, seven hundred seventy-nine".