84427991 has 2 divisors, whose sum is σ = 84427992. Its totient is φ = 84427990.

The previous prime is 84427957. The next prime is 84427999. The reversal of 84427991 is 19972448.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 84427991 - 2¹⁰ = 84426967 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (84427999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42213995 + 42213996.

It is an arithmetic number, because the mean of its divisors is an integer number (42213996).

Almost surely, 2^84427991 is an apocalyptic number.

84427991 is a deficient number, since it is larger than the sum of its proper divisors (1).

84427991 is an equidigital number, since it uses as much as digits as its factorization.

84427991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 44.

The square root of 84427991 is about 9188.4705473762. The cubic root of 84427991 is about 438.6944617379.

The spelling of 84427991 in words is "eighty-four million, four hundred twenty-seven thousand, nine hundred ninety-one".