71721931445 has 4 divisors (see below), whose sum is σ = 86066317740. Its totient is φ = 57377545152.

The previous prime is 71721931429. The next prime is 71721931459. The reversal of 71721931445 is 54413912717.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 42824991364 + 28896940081 = 206942^2 + 169991^2 .

It is a cyclic number.

It is not a de Polignac number, because 71721931445 - 2⁴ = 71721931429 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 71721931396 and 71721931405.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7172193140 + ... + 7172193149.

It is an arithmetic number, because the mean of its divisors is an integer number (21516579435).

Almost surely, 2^71721931445 is an apocalyptic number.

It is an amenable number.

71721931445 is a deficient number, since it is larger than the sum of its proper divisors (14344386295).

71721931445 is a wasteful number, since it uses less digits than its factorization.

71721931445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14344386294.

The product of its digits is 211680, while the sum is 44.

The spelling of 71721931445 in words is "seventy-one billion, seven hundred twenty-one million, nine hundred thirty-one thousand, four hundred forty-five".