71221751 has 4 divisors (see below), whose sum is σ = 71318352. Its totient is φ = 71125152.

The previous prime is 71221741. The next prime is 71221757. The reversal of 71221751 is 15712217.

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

It is a cyclic number.

It is not a de Polignac number, because 71221751 - 2¹⁰ = 71220727 is a prime.

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 71221751.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71221757) 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, 47186 + ... + 48671.

It is an arithmetic number, because the mean of its divisors is an integer number (17829588).

Almost surely, 2^71221751 is an apocalyptic number.

71221751 is a deficient number, since it is larger than the sum of its proper divisors (96601).

71221751 is an equidigital number, since it uses as much as digits as its factorization.

71221751 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96600.

The product of its digits is 980, while the sum is 26.

The square root of 71221751 is about 8439.2980158305. The cubic root of 71221751 is about 414.5124210345.

Adding to 71221751 its reverse (15712217), we get a palindrome (86933968).

The spelling of 71221751 in words is "seventy-one million, two hundred twenty-one thousand, seven hundred fifty-one".