42045561 has 24 divisors (see below), whose sum is σ = 63895104. Its totient is φ = 27624240.

The previous prime is 42045533. The next prime is 42045581. The reversal of 42045561 is 16554024.

It is not a de Polignac number, because 42045561 - 2¹¹ = 42043513 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

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

It is not an unprimeable number, because it can be changed into a prime (42045511) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16035 + ... + 18471.

It is an arithmetic number, because the mean of its divisors is an integer number (2662296).

Almost surely, 2^42045561 is an apocalyptic number.

It is an amenable number.

42045561 is a deficient number, since it is larger than the sum of its proper divisors (21849543).

42045561 is an equidigital number, since it uses as much as digits as its factorization.

42045561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2523 (or 2511 counting only the distinct ones).

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

The square root of 42045561 is about 6484.2548531038. The cubic root of 42045561 is about 347.7283105348.

Adding to 42045561 its reverse (16554024), we get a palindrome (58599585).

The spelling of 42045561 in words is "forty-two million, forty-five thousand, five hundred sixty-one".