42668981 has 4 divisors (see below), whose sum is σ = 42955500. Its totient is φ = 42382464.

The previous prime is 42668959. The next prime is 42668993. The reversal of 42668981 is 18986624.

It is a happy number.

42668981 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.

It can be written as a sum of positive squares in 2 ways, for example, as 27730756 + 14938225 = 5266^2 + 3865^2 .

It is a cyclic number.

It is not a de Polignac number, because 42668981 - 2⁶ = 42668917 is a prime.

It is a super-2 number, since 2×42668981² = 3641283879156722, 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 (42668921) 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, 143036 + ... + 143333.

It is an arithmetic number, because the mean of its divisors is an integer number (10738875).

Almost surely, 2^42668981 is an apocalyptic number.

It is an amenable number.

42668981 is a deficient number, since it is larger than the sum of its proper divisors (286519).

42668981 is a wasteful number, since it uses less digits than its factorization.

42668981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 286518.

The product of its digits is 165888, while the sum is 44.

The square root of 42668981 is about 6532.1497992621. The cubic root of 42668981 is about 349.4385037690.

The spelling of 42668981 in words is "forty-two million, six hundred sixty-eight thousand, nine hundred eighty-one".