1538328311521 has 4 divisors (see below), whose sum is σ = 1538561151232. Its totient is φ = 1538095471812.

The previous prime is 1538328311519. The next prime is 1538328311549. The reversal of 1538328311521 is 1251138238351.

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 1538328311521 - 2¹ = 1538328311519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1538328311591) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 116409945 + ... + 116423158.

It is an arithmetic number, because the mean of its divisors is an integer number (384640287808).

Almost surely, 2^{1538328311521} is an apocalyptic number.

It is an amenable number.

1538328311521 is a deficient number, since it is larger than the sum of its proper divisors (232839711).

1538328311521 is an equidigital number, since it uses as much as digits as its factorization.

1538328311521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 232839710.

The product of its digits is 172800, while the sum is 43.

The spelling of 1538328311521 in words is "one trillion, five hundred thirty-eight billion, three hundred twenty-eight million, three hundred eleven thousand, five hundred twenty-one".