81963091 has 4 divisors (see below), whose sum is σ = 93672112. Its totient is φ = 70254072.

The previous prime is 81963071. The next prime is 81963097. The reversal of 81963091 is 19036918.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 81963091 - 2¹¹ = 81961043 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81963091.

It is not an unprimeable number, because it can be changed into a prime (81963097) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5854500 + ... + 5854513.

It is an arithmetic number, because the mean of its divisors is an integer number (23418028).

Almost surely, 2^81963091 is an apocalyptic number.

81963091 is a deficient number, since it is larger than the sum of its proper divisors (11709021).

81963091 is a wasteful number, since it uses less digits than its factorization.

81963091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11709020.

The product of its (nonzero) digits is 11664, while the sum is 37.

The square root of 81963091 is about 9053.3469501616. The cubic root of 81963091 is about 434.3829556778.

The spelling of 81963091 in words is "eighty-one million, nine hundred sixty-three thousand, ninety-one".