71238781 has 4 divisors (see below), whose sum is σ = 71904672. Its totient is φ = 70572892.

The previous prime is 71238757. The next prime is 71238787. The reversal of 71238781 is 18783217.

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: 18783217 = 43 ⋅436819.

It is a cyclic number.

It is not a de Polignac number, because 71238781 - 2⁵ = 71238749 is a prime.

It is a super-2 number, since 2×71238781² = 10149927836731922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 71238781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71238787) 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, 332785 + ... + 332998.

It is an arithmetic number, because the mean of its divisors is an integer number (17976168).

Almost surely, 2^71238781 is an apocalyptic number.

It is an amenable number.

71238781 is a deficient number, since it is larger than the sum of its proper divisors (665891).

71238781 is a wasteful number, since it uses less digits than its factorization.

71238781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 665890.

The product of its digits is 18816, while the sum is 37.

The square root of 71238781 is about 8440.3069256989. The cubic root of 71238781 is about 414.5454567475.

It can be divided in two parts, 712 and 38781, that added together give a palindrome (39493).

The spelling of 71238781 in words is "seventy-one million, two hundred thirty-eight thousand, seven hundred eighty-one".