42090840 has 160 divisors (see below), whose sum is σ = 154463760. Its totient is φ = 10195200.

The previous prime is 42090821. The next prime is 42090857. The reversal of 42090840 is 4809024.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 35050 + ... + 36230.

Almost surely, 2^42090840 is an apocalyptic number.

42090840 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 42090840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (77231880).

42090840 is an abundant number, since it is smaller than the sum of its proper divisors (112372920).

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

42090840 is a wasteful number, since it uses less digits than its factorization.

42090840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1215 (or 1202 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 42090840 is about 6487.7453710823. The cubic root of 42090840 is about 347.8530889998.

Adding to 42090840 its reverse (4809024), we get a palindrome (46899864).

The spelling of 42090840 in words is "forty-two million, ninety thousand, eight hundred forty".