42557781 has 16 divisors (see below), whose sum is σ = 66075264. Its totient is φ = 23859264.

The previous prime is 42557747. The next prime is 42557791. The reversal of 42557781 is 18775524.

It is not a de Polignac number, because 42557781 - 2¹⁰ = 42556757 is a prime.

It is a super-2 number, since 2×42557781² = 3622329447287922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42557791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18006 + ... + 20231.

It is an arithmetic number, because the mean of its divisors is an integer number (4129704).

Almost surely, 2^42557781 is an apocalyptic number.

It is an amenable number.

42557781 is a deficient number, since it is larger than the sum of its proper divisors (23517483).

42557781 is a wasteful number, since it uses less digits than its factorization.

42557781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38300.

The product of its digits is 78400, while the sum is 39.

The square root of 42557781 is about 6523.6325003789. The cubic root of 42557781 is about 349.1346814501.

The spelling of 42557781 in words is "forty-two million, five hundred fifty-seven thousand, seven hundred eighty-one".