71397443209 has 3 divisors (see below), whose sum is σ = 71397710413. Its totient is φ = 71397176006.

The previous prime is 71397443189. The next prime is 71397443213. The reversal of 71397443209 is 90234479317.

The square root of 71397443209 is 267203.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a de Polignac number, because none of the positive numbers 2^k-71397443209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71397441209) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 133602 + ... + 400804.

Almost surely, 2^71397443209 is an apocalyptic number.

71397443209 is the 267203-rd square number.

71397443209 is the 133602-nd centered octagonal number.

It is an amenable number.

71397443209 is a deficient number, since it is larger than the sum of its proper divisors (267204).

71397443209 is an frugal number, since it uses more digits than its factorization.

71397443209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 534406 (or 267203 counting only the distinct ones).

The product of its (nonzero) digits is 1143072, while the sum is 49.

Multiplying 71397443209 by its sum of digits (49), we get a square (3498474717241 = 1870421²).

The spelling of 71397443209 in words is "seventy-one billion, three hundred ninety-seven million, four hundred forty-three thousand, two hundred nine".