42121540 has 24 divisors (see below), whose sum is σ = 90847512. Its totient is φ = 16392960.

The previous prime is 42121501. The next prime is 42121549. The reversal of 42121540 is 4512124.

It can be written as a sum of positive squares in 4 ways, for example, as 21455424 + 20666116 = 4632^2 + 4546^2 .

It is not an unprimeable number, because it can be changed into a prime (42121549) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27721 + ... + 29200.

It is an arithmetic number, because the mean of its divisors is an integer number (3785313).

Almost surely, 2^42121540 is an apocalyptic number.

It is an amenable number.

42121540 is an abundant number, since it is smaller than the sum of its proper divisors (48725972).

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

42121540 is a wasteful number, since it uses less digits than its factorization.

42121540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56967 (or 56965 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 42121540 is about 6490.1109389594. The cubic root of 42121540 is about 347.9376402112.

Adding to 42121540 its reverse (4512124), we get a palindrome (46633664).

The spelling of 42121540 in words is "forty-two million, one hundred twenty-one thousand, five hundred forty".