42391781 has 8 divisors (see below), whose sum is σ = 42834624. Its totient is φ = 41951520.

The previous prime is 42391759. The next prime is 42391861. The reversal of 42391781 is 18719324.

42391781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 42391781 - 2²² = 38197477 is a prime.

It is a super-2 number, since 2×42391781² = 3594126192703922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42391721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51866 + ... + 52676.

It is an arithmetic number, because the mean of its divisors is an integer number (5354328).

Almost surely, 2^42391781 is an apocalyptic number.

It is an amenable number.

42391781 is a deficient number, since it is larger than the sum of its proper divisors (442843).

42391781 is a wasteful number, since it uses less digits than its factorization.

42391781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1291.

The product of its digits is 12096, while the sum is 35.

The square root of 42391781 is about 6510.8970964069. The cubic root of 42391781 is about 348.6801474501.

The spelling of 42391781 in words is "forty-two million, three hundred ninety-one thousand, seven hundred eighty-one".