42951781 has 4 divisors (see below), whose sum is σ = 43290112. Its totient is φ = 42613452.

The previous prime is 42951773. The next prime is 42951803. The reversal of 42951781 is 18715924.

42951781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 42951781 - 2³ = 42951773 is a prime.

It is a super-2 number, since 2×42951781² = 3689710982143922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 42951781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42951751) 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 3 ways as a sum of consecutive naturals, for example, 168975 + ... + 169228.

It is an arithmetic number, because the mean of its divisors is an integer number (10822528).

Almost surely, 2^42951781 is an apocalyptic number.

It is an amenable number.

42951781 is a deficient number, since it is larger than the sum of its proper divisors (338331).

42951781 is a wasteful number, since it uses less digits than its factorization.

42951781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 338330.

The product of its digits is 20160, while the sum is 37.

The square root of 42951781 is about 6553.7608287151. The cubic root of 42951781 is about 350.2088032983.

The spelling of 42951781 in words is "forty-two million, nine hundred fifty-one thousand, seven hundred eighty-one".