42809731 has 2 divisors, whose sum is σ = 42809732. Its totient is φ = 42809730.

The previous prime is 42809719. The next prime is 42809747. The reversal of 42809731 is 13790824.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 42809731 - 2⁹ = 42809219 is a prime.

It is a super-2 number, since 2×42809731² = 3665346136584722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (42809131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21404865 + 21404866.

It is an arithmetic number, because the mean of its divisors is an integer number (21404866).

Almost surely, 2^42809731 is an apocalyptic number.

42809731 is a deficient number, since it is larger than the sum of its proper divisors (1).

42809731 is an equidigital number, since it uses as much as digits as its factorization.

42809731 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12096, while the sum is 34.

The square root of 42809731 is about 6542.9145646264. The cubic root of 42809731 is about 349.8223070805.

The spelling of 42809731 in words is "forty-two million, eight hundred nine thousand, seven hundred thirty-one".