81957340 has 24 divisors (see below), whose sum is σ = 182235312. Its totient is φ = 30854400.

The previous prime is 81957329. The next prime is 81957347. The reversal of 81957340 is 4375918.

It is a self number, because there is not a number n which added to its sum of digits gives 81957340.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81957347) by changing a digit.

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, 120186 + ... + 120865.

It is an arithmetic number, because the mean of its divisors is an integer number (7593138).

Almost surely, 2^81957340 is an apocalyptic number.

It is an amenable number.

81957340 is an abundant number, since it is smaller than the sum of its proper divisors (100277972).

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

81957340 is a wasteful number, since it uses less digits than its factorization.

81957340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241077 (or 241075 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 37.

The square root of 81957340 is about 9053.0293272473. The cubic root of 81957340 is about 434.3727958413.

The spelling of 81957340 in words is "eighty-one million, nine hundred fifty-seven thousand, three hundred forty".