81935816 has 8 divisors (see below), whose sum is σ = 153629670. Its totient is φ = 40967904.

The previous prime is 81935813. The next prime is 81935863. The reversal of 81935816 is 61853918.

It can be written as a sum of positive squares in only one way, i.e., 80102500 + 1833316 = 8950^2 + 1354^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (81935813) 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 as a sum of consecutive naturals, namely, 5120981 + ... + 5120996.

Almost surely, 2^81935816 is an apocalyptic number.

It is an amenable number.

81935816 is a deficient number, since it is larger than the sum of its proper divisors (71693854).

81935816 is a wasteful number, since it uses less digits than its factorization.

81935816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10241983 (or 10241979 counting only the distinct ones).

The product of its digits is 51840, while the sum is 41.

The square root of 81935816 is about 9051.8404758369. The cubic root of 81935816 is about 434.3347668755.

The spelling of 81935816 in words is "eighty-one million, nine hundred thirty-five thousand, eight hundred sixteen".