84517981 has 6 divisors (see below), whose sum is σ = 84995610. Its totient is φ = 84043008.

The previous prime is 84517969. The next prime is 84517991. The reversal of 84517981 is 18971548.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 2325625 + 82192356 = 1525^2 + 9066^2 .

It is not a de Polignac number, because 84517981 - 2¹⁷ = 84386909 is a prime.

It is a super-2 number, since 2×84517981² = 14286578224632722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (84517921) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 36115 + ... + 38383.

It is an arithmetic number, because the mean of its divisors is an integer number (14165935).

Almost surely, 2^84517981 is an apocalyptic number.

It is an amenable number.

84517981 is a deficient number, since it is larger than the sum of its proper divisors (477629).

84517981 is an equidigital number, since it uses as much as digits as its factorization.

84517981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2655 (or 2462 counting only the distinct ones).

The product of its digits is 80640, while the sum is 43.

The square root of 84517981 is about 9193.3661408648. The cubic root of 84517981 is about 438.8502714252.

The spelling of 84517981 in words is "eighty-four million, five hundred seventeen thousand, nine hundred eighty-one".