71672721 has 4 divisors (see below), whose sum is σ = 95563632. Its totient is φ = 47781812.

The previous prime is 71672687. The next prime is 71672729. The reversal of 71672721 is 12727617.

It is a happy number.

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 71672721 - 2¹¹ = 71670673 is a prime.

It is not an unprimeable number, because it can be changed into a prime (71672729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11945451 + ... + 11945456.

It is an arithmetic number, because the mean of its divisors is an integer number (23890908).

Almost surely, 2^71672721 is an apocalyptic number.

It is an amenable number.

71672721 is a deficient number, since it is larger than the sum of its proper divisors (23890911).

71672721 is a wasteful number, since it uses less digits than its factorization.

71672721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23890910.

The product of its digits is 8232, while the sum is 33.

The square root of 71672721 is about 8465.9743089617. The cubic root of 71672721 is about 415.3854665990.

It can be divided in two parts, 716 and 72721, that added together give a palindrome (73437).

The spelling of 71672721 in words is "seventy-one million, six hundred seventy-two thousand, seven hundred twenty-one".