743971721 has 4 divisors (see below), whose sum is σ = 748082244. Its totient is φ = 739861200.

The previous prime is 743971703. The next prime is 743971727. The reversal of 743971721 is 127179347.

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

It can be written as a sum of positive squares in 2 ways, for example, as 236821321 + 507150400 = 15389^2 + 22520^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-743971721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (743971727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2054990 + ... + 2055351.

It is an arithmetic number, because the mean of its divisors is an integer number (187020561).

Almost surely, 2^743971721 is an apocalyptic number.

It is an amenable number.

743971721 is a deficient number, since it is larger than the sum of its proper divisors (4110523).

743971721 is a wasteful number, since it uses less digits than its factorization.

743971721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4110522.

The product of its digits is 74088, while the sum is 41.

The square root of 743971721 is about 27275.8450098251. The cubic root of 743971721 is about 906.1194985704.

The spelling of 743971721 in words is "seven hundred forty-three million, nine hundred seventy-one thousand, seven hundred twenty-one".