3123491721 has 24 divisors (see below), whose sum is σ = 4882775040. Its totient is φ = 1770787872.

The previous prime is 3123491687. The next prime is 3123491729. The reversal of 3123491721 is 1271943213.

3123491721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 3123491721 - 2¹⁰ = 3123490697 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (3123491729) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 64986 + ... + 102323.

It is an arithmetic number, because the mean of its divisors is an integer number (203448960).

Almost surely, 2^3123491721 is an apocalyptic number.

It is an amenable number.

3123491721 is a deficient number, since it is larger than the sum of its proper divisors (1759283319).

3123491721 is a wasteful number, since it uses less digits than its factorization.

3123491721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167453 (or 167446 counting only the distinct ones).

The product of its digits is 9072, while the sum is 33.

The square root of 3123491721 is about 55888.2073518198. The cubic root of 3123491721 is about 1461.7736187452.

The spelling of 3123491721 in words is "three billion, one hundred twenty-three million, four hundred ninety-one thousand, seven hundred twenty-one".