78717971 has 4 divisors (see below), whose sum is σ = 78741432. Its totient is φ = 78694512.

The previous prime is 78717943. The next prime is 78717979. The reversal of 78717971 is 17971787.

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 78717971 - 2²⁶ = 11609107 is a prime.

It is a super-3 number, since 3×78717971³ (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 (78717979) 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, 5645 + ... + 13758.

It is an arithmetic number, because the mean of its divisors is an integer number (19685358).

Almost surely, 2^78717971 is an apocalyptic number.

78717971 is a deficient number, since it is larger than the sum of its proper divisors (23461).

78717971 is a wasteful number, since it uses less digits than its factorization.

78717971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23460.

The product of its digits is 172872, while the sum is 47.

The square root of 78717971 is about 8872.3148614102. The cubic root of 78717971 is about 428.5728256727.

The spelling of 78717971 in words is "seventy-eight million, seven hundred seventeen thousand, nine hundred seventy-one".