84378512081 has 2 divisors, whose sum is σ = 84378512082. Its totient is φ = 84378512080.

The previous prime is 84378512069. The next prime is 84378512083. The reversal of 84378512081 is 18021587348.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 68361331600 + 16017180481 = 261460^2 + 126559^2 .

It is a cyclic number.

It is not a de Polignac number, because 84378512081 - 2³⁰ = 83304770257 is a prime.

It is a super-2 number, since 2×84378512081² (a number of 23 digits) contains 22 as substring.

Together with 84378512083, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (84378512083) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42189256040 + 42189256041.

It is an arithmetic number, because the mean of its divisors is an integer number (42189256041).

Almost surely, 2^84378512081 is an apocalyptic number.

It is an amenable number.

84378512081 is a deficient number, since it is larger than the sum of its proper divisors (1).

84378512081 is an equidigital number, since it uses as much as digits as its factorization.

84378512081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 430080, while the sum is 47.

The spelling of 84378512081 in words is "eighty-four billion, three hundred seventy-eight million, five hundred twelve thousand, eighty-one".