71991899 has 8 divisors (see below), whose sum is σ = 84500448. Its totient is φ = 60039360.

The previous prime is 71991869. The next prime is 71991901. The reversal of 71991899 is 99819917.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 71991899 - 2¹² = 71987803 is a prime.

It is a super-3 number, since 3×71991899³ (a number of 25 digits) contains 333 as substring.

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 71991899.

It is not an unprimeable number, because it can be changed into a prime (71991839) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 138722 + ... + 139239.

It is an arithmetic number, because the mean of its divisors is an integer number (10562556).

Almost surely, 2^71991899 is an apocalyptic number.

71991899 is a deficient number, since it is larger than the sum of its proper divisors (12508549).

71991899 is a wasteful number, since it uses less digits than its factorization.

71991899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 278005.

The product of its digits is 367416, while the sum is 53.

The square root of 71991899 is about 8484.8040048077. The cubic root of 71991899 is about 416.0011614705.

The spelling of 71991899 in words is "seventy-one million, nine hundred ninety-one thousand, eight hundred ninety-nine".