71725721 has 4 divisors (see below), whose sum is σ = 73664292. Its totient is φ = 69787152.

The previous prime is 71725681. The next prime is 71725739. The reversal of 71725721 is 12752717.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12752717 = 181 ⋅70457.

It can be written as a sum of positive squares in 2 ways, for example, as 38502025 + 33223696 = 6205^2 + 5764^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71725721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71725321) 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, 969230 + ... + 969303.

It is an arithmetic number, because the mean of its divisors is an integer number (18416073).

Almost surely, 2^71725721 is an apocalyptic number.

It is an amenable number.

71725721 is a deficient number, since it is larger than the sum of its proper divisors (1938571).

71725721 is a wasteful number, since it uses less digits than its factorization.

71725721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1938570.

The product of its digits is 6860, while the sum is 32.

The square root of 71725721 is about 8469.1039077343. The cubic root of 71725721 is about 415.4878300693.

The spelling of 71725721 in words is "seventy-one million, seven hundred twenty-five thousand, seven hundred twenty-one".