42778399 has 4 divisors (see below), whose sum is σ = 42872464. Its totient is φ = 42684336.

The previous prime is 42778391. The next prime is 42778403. The reversal of 42778399 is 99387724.

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 42778399 - 2³ = 42778391 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42778391) 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, 46347 + ... + 47260.

It is an arithmetic number, because the mean of its divisors is an integer number (10718116).

Almost surely, 2^42778399 is an apocalyptic number.

42778399 is a deficient number, since it is larger than the sum of its proper divisors (94065).

42778399 is an equidigital number, since it uses as much as digits as its factorization.

42778399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94064.

The product of its digits is 762048, while the sum is 49.

The square root of 42778399 is about 6540.5197805679. The cubic root of 42778399 is about 349.7369424734.

The spelling of 42778399 in words is "forty-two million, seven hundred seventy-eight thousand, three hundred ninety-nine".