1533321721 has 8 divisors (see below), whose sum is σ = 1586469888. Its totient is φ = 1480404000.

The previous prime is 1533321719. The next prime is 1533321781. The reversal of 1533321721 is 1271233351.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1533321721 - 2¹ = 1533321719 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1533321721.

It is not an unprimeable number, because it can be changed into a prime (1533321781) 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 7 ways as a sum of consecutive naturals, for example, 44020 + ... + 70741.

It is an arithmetic number, because the mean of its divisors is an integer number (198308736).

Almost surely, 2^1533321721 is an apocalyptic number.

It is an amenable number.

1533321721 is a deficient number, since it is larger than the sum of its proper divisors (53148167).

1533321721 is a wasteful number, since it uses less digits than its factorization.

1533321721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115223.

The product of its digits is 3780, while the sum is 28.

The square root of 1533321721 is about 39157.6521385029. The cubic root of 1533321721 is about 1153.1286503372.

The spelling of 1533321721 in words is "one billion, five hundred thirty-three million, three hundred twenty-one thousand, seven hundred twenty-one".