42247991 has 2 divisors, whose sum is σ = 42247992. Its totient is φ = 42247990.

The previous prime is 42247979. The next prime is 42247993. The reversal of 42247991 is 19974224.

42247991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 42247991 - 2⁶ = 42247927 is a prime.

Together with 42247993, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p_2561798 and since 42247991 and 2561798 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42247993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21123995 + 21123996.

It is an arithmetic number, because the mean of its divisors is an integer number (21123996).

Almost surely, 2^42247991 is an apocalyptic number.

42247991 is a deficient number, since it is larger than the sum of its proper divisors (1).

42247991 is an equidigital number, since it uses as much as digits as its factorization.

42247991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 38.

The square root of 42247991 is about 6499.8454597013. The cubic root of 42247991 is about 348.2854678601.

The spelling of 42247991 in words is "forty-two million, two hundred forty-seven thousand, nine hundred ninety-one".