71813999 has 4 divisors (see below), whose sum is σ = 73484136. Its totient is φ = 70143864.

The previous prime is 71813957. The next prime is 71814023. The reversal of 71813999 is 99931817.

It is a happy number.

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 71813999 - 2⁸ = 71813743 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71813909) 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, 835004 + ... + 835089.

It is an arithmetic number, because the mean of its divisors is an integer number (18371034).

Almost surely, 2^71813999 is an apocalyptic number.

71813999 is a deficient number, since it is larger than the sum of its proper divisors (1670137).

71813999 is a wasteful number, since it uses less digits than its factorization.

71813999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1670136.

The product of its digits is 122472, while the sum is 47.

The square root of 71813999 is about 8474.3140725371. The cubic root of 71813999 is about 415.6582170976.

The spelling of 71813999 in words is "seventy-one million, eight hundred thirteen thousand, nine hundred ninety-nine".