81958740 has 24 divisors (see below), whose sum is σ = 229484640. Its totient is φ = 21855648.

The previous prime is 81958739. The next prime is 81958753. The reversal of 81958740 is 4785918.

It is a junction number, because it is equal to n+sod(n) for n = 81958692 and 81958701.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 682930 + ... + 683049.

It is an arithmetic number, because the mean of its divisors is an integer number (9561860).

Almost surely, 2^81958740 is an apocalyptic number.

It is an amenable number.

81958740 is an abundant number, since it is smaller than the sum of its proper divisors (147525900).

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

81958740 is a wasteful number, since it uses less digits than its factorization.

81958740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1365991 (or 1365989 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 42.

The square root of 81958740 is about 9053.1066491012. The cubic root of 81958740 is about 434.3752691543.

The spelling of 81958740 in words is "eighty-one million, nine hundred fifty-eight thousand, seven hundred forty".