42006640 has 80 divisors (see below), whose sum is σ = 106243200. Its totient is φ = 15445248.

The previous prime is 42006631. The next prime is 42006659. The reversal of 42006640 is 4660024.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-3 number, since 3×42006640³ (a number of 24 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 175641 + ... + 175879.

It is an arithmetic number, because the mean of its divisors is an integer number (1328040).

Almost surely, 2^42006640 is an apocalyptic number.

42006640 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 42006640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (53121600).

42006640 is an abundant number, since it is smaller than the sum of its proper divisors (64236560).

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

42006640 is a wasteful number, since it uses less digits than its factorization.

42006640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 291 (or 259 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 22.

The square root of 42006640 is about 6481.2529652838. The cubic root of 42006640 is about 347.6209816321.

Adding to 42006640 its reverse (4660024), we get a palindrome (46666664).

The spelling of 42006640 in words is "forty-two million, six thousand, six hundred forty".