71725781 has 4 divisors (see below), whose sum is σ = 71743200. Its totient is φ = 71708364.

The previous prime is 71725747. The next prime is 71725783. The reversal of 71725781 is 18752717.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18752717 = 17 ⋅1103101.

It is a cyclic number.

It is not a de Polignac number, because 71725781 - 2¹⁴ = 71709397 is a prime.

It is a super-2 number, since 2×71725781² = 10289175320119922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71725783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1310 + ... + 12048.

It is an arithmetic number, because the mean of its divisors is an integer number (17935800).

Almost surely, 2^71725781 is an apocalyptic number.

71725781 is the 3788-th centered decagonal number.

It is an amenable number.

71725781 is a deficient number, since it is larger than the sum of its proper divisors (17419).

71725781 is a wasteful number, since it uses less digits than its factorization.

71725781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17418.

The product of its digits is 27440, while the sum is 38.

The square root of 71725781 is about 8469.1074500209. The cubic root of 71725781 is about 415.4879459239.

The spelling of 71725781 in words is "seventy-one million, seven hundred twenty-five thousand, seven hundred eighty-one".