81919363 has 4 divisors (see below), whose sum is σ = 81938440. Its totient is φ = 81900288.

The previous prime is 81919361. The next prime is 81919373. The reversal of 81919363 is 36391918.

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

It is a cyclic number.

It is not a de Polignac number, because 81919363 - 2¹ = 81919361 is a prime.

It is a super-3 number, since 3×81919363³ (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81919361) 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, 256 + ... + 12802.

It is an arithmetic number, because the mean of its divisors is an integer number (20484610).

Almost surely, 2^81919363 is an apocalyptic number.

81919363 is a deficient number, since it is larger than the sum of its proper divisors (19077).

81919363 is a wasteful number, since it uses less digits than its factorization.

81919363 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19076.

The product of its digits is 34992, while the sum is 40.

The square root of 81919363 is about 9050.9316095085. The cubic root of 81919363 is about 434.3056929465.

The spelling of 81919363 in words is "eighty-one million, nine hundred nineteen thousand, three hundred sixty-three".