42187979 has 2 divisors, whose sum is σ = 42187980. Its totient is φ = 42187978.

The previous prime is 42187969. The next prime is 42187991. The reversal of 42187979 is 97978124.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 42187979 - 2⁴ = 42187963 is a prime.

It is not a weakly prime, because it can be changed into another prime (42187909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21093989 + 21093990.

It is an arithmetic number, because the mean of its divisors is an integer number (21093990).

Almost surely, 2^42187979 is an apocalyptic number.

42187979 is a deficient number, since it is larger than the sum of its proper divisors (1).

42187979 is an equidigital number, since it uses as much as digits as its factorization.

42187979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 254016, while the sum is 47.

The square root of 42187979 is about 6495.2274017158. The cubic root of 42187979 is about 348.1204800396.

The spelling of 42187979 in words is "forty-two million, one hundred eighty-seven thousand, nine hundred seventy-nine".