81541916 has 6 divisors (see below), whose sum is σ = 142698360. Its totient is φ = 40770956.

The previous prime is 81541909. The next prime is 81541927. The reversal of 81541916 is 61914518.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10192736 + ... + 10192743.

It is an arithmetic number, because the mean of its divisors is an integer number (23783060).

Almost surely, 2^81541916 is an apocalyptic number.

It is an amenable number.

81541916 is a deficient number, since it is larger than the sum of its proper divisors (61156444).

81541916 is a wasteful number, since it uses less digits than its factorization.

81541916 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20385483 (or 20385481 counting only the distinct ones).

The product of its digits is 8640, while the sum is 35.

The square root of 81541916 is about 9030.0562567461. The cubic root of 81541916 is about 433.6376384565.

The spelling of 81541916 in words is "eighty-one million, five hundred forty-one thousand, nine hundred sixteen".