84115981 has 2 divisors, whose sum is σ = 84115982. Its totient is φ = 84115980.

The previous prime is 84115973. The next prime is 84116003. The reversal of 84115981 is 18951148.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 58522500 + 25593481 = 7650^2 + 5059^2 .

It is a cyclic number.

It is not a de Polignac number, because 84115981 - 2³ = 84115973 is a prime.

It is a super-2 number, since 2×84115981² = 14150996519184722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 84115981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (84115951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42057990 + 42057991.

It is an arithmetic number, because the mean of its divisors is an integer number (42057991).

Almost surely, 2^84115981 is an apocalyptic number.

It is an amenable number.

84115981 is a deficient number, since it is larger than the sum of its proper divisors (1).

84115981 is an equidigital number, since it uses as much as digits as its factorization.

84115981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11520, while the sum is 37.

The square root of 84115981 is about 9171.4764896390. The cubic root of 84115981 is about 438.1533851843.

The spelling of 84115981 in words is "eighty-four million, one hundred fifteen thousand, nine hundred eighty-one".