71771721 has 32 divisors (see below), whose sum is σ = 117504000. Its totient is φ = 38843280.

The previous prime is 71771719. The next prime is 71771731. The reversal of 71771721 is 12717717.

It is a happy number.

It is not a de Polignac number, because 71771721 - 2¹ = 71771719 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71771701) 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 31 ways as a sum of consecutive naturals, for example, 17716 + ... + 21386.

It is an arithmetic number, because the mean of its divisors is an integer number (3672000).

Almost surely, 2^71771721 is an apocalyptic number.

It is an amenable number.

71771721 is a deficient number, since it is larger than the sum of its proper divisors (45732279).

71771721 is a wasteful number, since it uses less digits than its factorization.

71771721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3714 (or 3700 counting only the distinct ones).

The product of its digits is 4802, while the sum is 33.

The square root of 71771721 is about 8471.8192261167. The cubic root of 71771721 is about 415.5766329682.

The spelling of 71771721 in words is "seventy-one million, seven hundred seventy-one thousand, seven hundred twenty-one".