71745781 has 4 divisors (see below), whose sum is σ = 72610272. Its totient is φ = 70881292.

The previous prime is 71745761. The next prime is 71745799. The reversal of 71745781 is 18754717.

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.

It is a cyclic number.

It is not a de Polignac number, because 71745781 - 2⁹ = 71745269 is a prime.

It is a super-2 number, since 2×71745781² = 10294914182599922, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71745761) 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, 432121 + ... + 432286.

It is an arithmetic number, because the mean of its divisors is an integer number (18152568).

Almost surely, 2^71745781 is an apocalyptic number.

It is an amenable number.

71745781 is a deficient number, since it is larger than the sum of its proper divisors (864491).

71745781 is an equidigital number, since it uses as much as digits as its factorization.

71745781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 864490.

The product of its digits is 54880, while the sum is 40.

The square root of 71745781 is about 8470.2881296919. The cubic root of 71745781 is about 415.5265605223.

The spelling of 71745781 in words is "seventy-one million, seven hundred forty-five thousand, seven hundred eighty-one".