71506391321 has 16 divisors (see below), whose sum is σ = 76652956800. Its totient is φ = 66464901888.

The previous prime is 71506391293. The next prime is 71506391329. The reversal of 71506391321 is 12319360517.

It is a cyclic number.

It is not a de Polignac number, because 71506391321 - 2³⁴ = 54326522137 is a prime.

It is a super-2 number, since 2×71506391321² (a number of 23 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (71506391329) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4675475 + ... + 4690743.

It is an arithmetic number, because the mean of its divisors is an integer number (4790809800).

Almost surely, 2^71506391321 is an apocalyptic number.

It is an amenable number.

71506391321 is a deficient number, since it is larger than the sum of its proper divisors (5146565479).

71506391321 is a wasteful number, since it uses less digits than its factorization.

71506391321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18688.

The product of its (nonzero) digits is 34020, while the sum is 38.

The spelling of 71506391321 in words is "seventy-one billion, five hundred six million, three hundred ninety-one thousand, three hundred twenty-one".