42009971 has 2 divisors, whose sum is σ = 42009972. Its totient is φ = 42009970.

The previous prime is 42009959. The next prime is 42010013. The reversal of 42009971 is 17990024.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42009971 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (42009901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21004985 + 21004986.

It is an arithmetic number, because the mean of its divisors is an integer number (21004986).

Almost surely, 2^42009971 is an apocalyptic number.

42009971 is a deficient number, since it is larger than the sum of its proper divisors (1).

42009971 is an equidigital number, since it uses as much as digits as its factorization.

42009971 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4536, while the sum is 32.

The square root of 42009971 is about 6481.5099321069. The cubic root of 42009971 is about 347.6301698214.

Adding to 42009971 its reverse (17990024), we get a palindrome (59999995).

The spelling of 42009971 in words is "forty-two million, nine thousand, nine hundred seventy-one".