84378512021 has 2 divisors, whose sum is σ = 84378512022. Its totient is φ = 84378512020.

The previous prime is 84378512003. The next prime is 84378512069. The reversal of 84378512021 is 12021587348.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51205353796 + 33173158225 = 226286^2 + 182135^2 .

It is a cyclic number.

It is not a de Polignac number, because 84378512021 - 2⁶ = 84378511957 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 84378512021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (84378512081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42189256010 + 42189256011.

It is an arithmetic number, because the mean of its divisors is an integer number (42189256011).

Almost surely, 2^84378512021 is an apocalyptic number.

It is an amenable number.

84378512021 is a deficient number, since it is larger than the sum of its proper divisors (1).

84378512021 is an equidigital number, since it uses as much as digits as its factorization.

84378512021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 107520, while the sum is 41.

The spelling of 84378512021 in words is "eighty-four billion, three hundred seventy-eight million, five hundred twelve thousand, twenty-one".