42219979 has 2 divisors, whose sum is σ = 42219980. Its totient is φ = 42219978.

The previous prime is 42219967. The next prime is 42220081. The reversal of 42219979 is 97991224.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42219979 is a prime.

It is not a weakly prime, because it can be changed into another prime (42219949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21109989 + 21109990.

It is an arithmetic number, because the mean of its divisors is an integer number (21109990).

Almost surely, 2^42219979 is an apocalyptic number.

42219979 is a deficient number, since it is larger than the sum of its proper divisors (1).

42219979 is an equidigital number, since it uses as much as digits as its factorization.

42219979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 81648, while the sum is 43.

The square root of 42219979 is about 6497.6902819387. The cubic root of 42219979 is about 348.2084754058.

The spelling of 42219979 in words is "forty-two million, two hundred nineteen thousand, nine hundred seventy-nine".