1398334721 has 4 divisors (see below), whose sum is σ = 1598096832. Its totient is φ = 1198572612.

The previous prime is 1398334661. The next prime is 1398334757. The reversal of 1398334721 is 1274338931.

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 1398334721 - 2¹⁰ = 1398333697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1398334771) 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, 99881045 + ... + 99881058.

It is an arithmetic number, because the mean of its divisors is an integer number (399524208).

Almost surely, 2^1398334721 is an apocalyptic number.

It is an amenable number.

1398334721 is a deficient number, since it is larger than the sum of its proper divisors (199762111).

1398334721 is an equidigital number, since it uses as much as digits as its factorization.

1398334721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199762110.

The product of its digits is 108864, while the sum is 41.

The square root of 1398334721 is about 37394.3140196474. The cubic root of 1398334721 is about 1118.2452115258.

The spelling of 1398334721 in words is "one billion, three hundred ninety-eight million, three hundred thirty-four thousand, seven hundred twenty-one".