42561540 has 144 divisors (see below), whose sum is σ = 156304512. Its totient is φ = 9151488.

The previous prime is 42561527. The next prime is 42561551. The reversal of 42561540 is 4516524.

42561540 is a `hidden beast` number, since 4 + 2 + 5 + 615 + 40 = 666.

It is a super-2 number, since 2×42561540² = 3622969374343200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 20427 + ... + 22413.

It is an arithmetic number, because the mean of its divisors is an integer number (1085448).

Almost surely, 2^42561540 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 42561540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (78152256).

42561540 is an abundant number, since it is smaller than the sum of its proper divisors (113742972).

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

42561540 is a wasteful number, since it uses less digits than its factorization.

42561540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2026 (or 2021 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The square root of 42561540 is about 6523.9206003752. The cubic root of 42561540 is about 349.1449604841.

The spelling of 42561540 in words is "forty-two million, five hundred sixty-one thousand, five hundred forty".