81958986 has 32 divisors (see below), whose sum is σ = 184020480. Its totient is φ = 27036288.

The previous prime is 81958969. The next prime is 81958993. The reversal of 81958986 is 68985918.

It is a super-2 number, since 2×81958986² = 13434550772296392, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

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 in 15 ways as a sum of consecutive naturals, for example, 2586 + ... + 13061.

It is an arithmetic number, because the mean of its divisors is an integer number (5750640).

Almost surely, 2^81958986 is an apocalyptic number.

81958986 is an abundant number, since it is smaller than the sum of its proper divisors (102061494).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81958986 is a wasteful number, since it uses less digits than its factorization.

81958986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15755 (or 15749 counting only the distinct ones).

The product of its digits is 1244160, while the sum is 54.

The square root of 81958986 is about 9053.1202355873. The cubic root of 81958986 is about 434.3757037478.

It can be divided in two parts, 81958 and 986, that added together give a square (82944 = 288²).

The spelling of 81958986 in words is "eighty-one million, nine hundred fifty-eight thousand, nine hundred eighty-six".