42778840 has 32 divisors (see below), whose sum is σ = 103657680. Its totient is φ = 15795072.

The previous prime is 42778819. The next prime is 42778847. The reversal of 42778840 is 4887724.

It is a happy number.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 42778793 and 42778802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42778847) 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, 40614 + ... + 41653.

Almost surely, 2^42778840 is an apocalyptic number.

42778840 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

42778840 is an abundant number, since it is smaller than the sum of its proper divisors (60878840).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

42778840 is a wasteful number, since it uses less digits than its factorization.

42778840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82291 (or 82287 counting only the distinct ones).

The product of its (nonzero) digits is 100352, while the sum is 40.

The square root of 42778840 is about 6540.5534933979. The cubic root of 42778840 is about 349.7381442751.

The spelling of 42778840 in words is "forty-two million, seven hundred seventy-eight thousand, eight hundred forty".