71397639 has 8 divisors (see below), whose sum is σ = 105774320. Its totient is φ = 47598408.

The previous prime is 71397631. The next prime is 71397647. The reversal of 71397639 is 93679317.

71397639 is a `hidden beast` number, since 7 + 1 + 3 + 9 + 7 + 639 = 666.

It is an interprime number because it is at equal distance from previous prime (71397631) and next prime (71397647).

It is not a de Polignac number, because 71397639 - 2³ = 71397631 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 71397594 and 71397603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71397631) 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, 1322152 + ... + 1322205.

It is an arithmetic number, because the mean of its divisors is an integer number (13221790).

Almost surely, 2^71397639 is an apocalyptic number.

71397639 is a deficient number, since it is larger than the sum of its proper divisors (34376681).

71397639 is a wasteful number, since it uses less digits than its factorization.

71397639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2644366 (or 2644360 counting only the distinct ones).

The product of its digits is 214326, while the sum is 45.

The square root of 71397639 is about 8449.7123619683. The cubic root of 71397639 is about 414.8533647521.

The spelling of 71397639 in words is "seventy-one million, three hundred ninety-seven thousand, six hundred thirty-nine".