71663509 has 4 divisors (see below), whose sum is σ = 71704480. Its totient is φ = 71622540.

The previous prime is 71663479. The next prime is 71663521. The reversal of 71663509 is 90536617.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 71663509 - 2⁵ = 71663477 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 (71663569) 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, 17739 + ... + 21400.

It is an arithmetic number, because the mean of its divisors is an integer number (17926120).

Almost surely, 2^71663509 is an apocalyptic number.

It is an amenable number.

71663509 is a deficient number, since it is larger than the sum of its proper divisors (40971).

71663509 is a wasteful number, since it uses less digits than its factorization.

71663509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40970.

The product of its (nonzero) digits is 34020, while the sum is 37.

The square root of 71663509 is about 8465.4302312405. The cubic root of 71663509 is about 415.3676695217.

The spelling of 71663509 in words is "seventy-one million, six hundred sixty-three thousand, five hundred nine".