1573738721 has 4 divisors (see below), whose sum is σ = 1575327744. Its totient is φ = 1572149700.

The previous prime is 1573738717. The next prime is 1573738753. The reversal of 1573738721 is 1278373751.

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 1573738721 - 2² = 1573738717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1573738121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 793025 + ... + 795006.

It is an arithmetic number, because the mean of its divisors is an integer number (393831936).

Almost surely, 2^1573738721 is an apocalyptic number.

It is an amenable number.

1573738721 is a deficient number, since it is larger than the sum of its proper divisors (1589023).

1573738721 is an equidigital number, since it uses as much as digits as its factorization.

1573738721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1589022.

The product of its digits is 246960, while the sum is 44.

The square root of 1573738721 is about 39670.3758615922. The cubic root of 1573738721 is about 1163.1727256067.

The spelling of 1573738721 in words is "one billion, five hundred seventy-three million, seven hundred thirty-eight thousand, seven hundred twenty-one".