42871781 has 2 divisors, whose sum is σ = 42871782. Its totient is φ = 42871780.

The previous prime is 42871757. The next prime is 42871811. The reversal of 42871781 is 18717824.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 39753025 + 3118756 = 6305^2 + 1766^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42871781 is a prime.

It is a super-2 number, since 2×42871781² = 3675979212223922, which contains 22 as substring.

It is a Chen prime.

It is a plaindrome in base 11.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42871711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21435890 + 21435891.

It is an arithmetic number, because the mean of its divisors is an integer number (21435891).

Almost surely, 2^42871781 is an apocalyptic number.

It is an amenable number.

42871781 is a deficient number, since it is larger than the sum of its proper divisors (1).

42871781 is an equidigital number, since it uses as much as digits as its factorization.

42871781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25088, while the sum is 38.

The square root of 42871781 is about 6547.6546182584. The cubic root of 42871781 is about 349.9912405971.

The spelling of 42871781 in words is "forty-two million, eight hundred seventy-one thousand, seven hundred eighty-one".