42978390 has 144 divisors (see below), whose sum is σ = 130679568. Its totient is φ = 9015552.

The previous prime is 42978317. The next prime is 42978391. The reversal of 42978390 is 9387924.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42978391) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 248344 + ... + 248516.

It is an arithmetic number, because the mean of its divisors is an integer number (907497).

Almost surely, 2^42978390 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 42978390, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (65339784).

42978390 is an abundant number, since it is smaller than the sum of its proper divisors (87701178).

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

42978390 is a wasteful number, since it uses less digits than its factorization.

42978390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223 (or 203 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 42.

The square root of 42978390 is about 6555.7905701753. The cubic root of 42978390 is about 350.2811074974.

The spelling of 42978390 in words is "forty-two million, nine hundred seventy-eight thousand, three hundred ninety".