84420251 has 2 divisors, whose sum is σ = 84420252. Its totient is φ = 84420250.

The previous prime is 84420233. The next prime is 84420253. The reversal of 84420251 is 15202448.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 84420251 - 2⁶ = 84420187 is a prime.

It is a super-3 number, since 3×84420251³ (a number of 25 digits) contains 333 as substring.

Together with 84420253, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 84420251.

It is not a weakly prime, because it can be changed into another prime (84420253) 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, 42210125 + 42210126.

It is an arithmetic number, because the mean of its divisors is an integer number (42210126).

Almost surely, 2^84420251 is an apocalyptic number.

84420251 is a deficient number, since it is larger than the sum of its proper divisors (1).

84420251 is an equidigital number, since it uses as much as digits as its factorization.

84420251 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2560, while the sum is 26.

The square root of 84420251 is about 9188.0493577255. The cubic root of 84420251 is about 438.6810554459.

Adding to 84420251 its reverse (15202448), we get a palindrome (99622699).

The spelling of 84420251 in words is "eighty-four million, four hundred twenty thousand, two hundred fifty-one".