42021240 has 64 divisors (see below), whose sum is σ = 127612800. Its totient is φ = 11068032.

The previous prime is 42021227. The next prime is 42021241. The reversal of 42021240 is 4212024.

It is a super-2 number, since 2×42021240² = 3531569222275200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42021241) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7851 + ... + 12069.

It is an arithmetic number, because the mean of its divisors is an integer number (1993950).

Almost surely, 2^42021240 is an apocalyptic number.

42021240 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 42021240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (63806400).

42021240 is an abundant number, since it is smaller than the sum of its proper divisors (85591560).

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

42021240 is a wasteful number, since it uses less digits than its factorization.

42021240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4316 (or 4312 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 15.

The square root of 42021240 is about 6482.3791928581. The cubic root of 42021240 is about 347.6612504916.

Adding to 42021240 its reverse (4212024), we get a palindrome (46233264).

The spelling of 42021240 in words is "forty-two million, twenty-one thousand, two hundred forty".