81949716 has 36 divisors (see below), whose sum is σ = 207913524. Its totient is φ = 27216000.

The previous prime is 81949669. The next prime is 81949729. The reversal of 81949716 is 61794918.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 74132100 + 7817616 = 8610^2 + 2796^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

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 11 ways as a sum of consecutive naturals, for example, 6066 + ... + 14166.

Almost surely, 2^81949716 is an apocalyptic number.

It is an amenable number.

81949716 is an abundant number, since it is smaller than the sum of its proper divisors (125963808).

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

81949716 is a wasteful number, since it uses less digits than its factorization.

81949716 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8392 (or 8387 counting only the distinct ones).

The product of its digits is 108864, while the sum is 45.

The square root of 81949716 is about 9052.6082429320. The cubic root of 81949716 is about 434.3593263913.

The spelling of 81949716 in words is "eighty-one million, nine hundred forty-nine thousand, seven hundred sixteen".