71663809 has 8 divisors (see below), whose sum is σ = 82627200. Its totient is φ = 60881856.

The previous prime is 71663797. The next prime is 71663821. The reversal of 71663809 is 90836617.

It is an interprime number because it is at equal distance from previous prime (71663797) and next prime (71663821).

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

It is a de Polignac number, because none of the positive numbers 2^k-71663809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71663869) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44509 + ... + 46090.

It is an arithmetic number, because the mean of its divisors is an integer number (10328400).

Almost surely, 2^71663809 is an apocalyptic number.

It is an amenable number.

71663809 is a deficient number, since it is larger than the sum of its proper divisors (10963391).

71663809 is a wasteful number, since it uses less digits than its factorization.

71663809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90719.

The product of its (nonzero) digits is 54432, while the sum is 40.

The square root of 71663809 is about 8465.4479503450. The cubic root of 71663809 is about 415.3682491292.

The spelling of 71663809 in words is "seventy-one million, six hundred sixty-three thousand, eight hundred nine".