42745561 has 4 divisors (see below), whose sum is σ = 42788772. Its totient is φ = 42702352.

The previous prime is 42745553. The next prime is 42745579. The reversal of 42745561 is 16554724.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1336336 + 41409225 = 1156^2 + 6435^2 .

It is a cyclic number.

It is not a de Polignac number, because 42745561 - 2³ = 42745553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42745511) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20086 + ... + 22111.

It is an arithmetic number, because the mean of its divisors is an integer number (10697193).

Almost surely, 2^42745561 is an apocalyptic number.

It is an amenable number.

42745561 is a deficient number, since it is larger than the sum of its proper divisors (43211).

42745561 is a wasteful number, since it uses less digits than its factorization.

42745561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43210.

The product of its digits is 33600, while the sum is 34.

The square root of 42745561 is about 6538.0089476843. The cubic root of 42745561 is about 349.6474299944.

The spelling of 42745561 in words is "forty-two million, seven hundred forty-five thousand, five hundred sixty-one".