1538793121021 has 8 divisors (see below), whose sum is σ = 1754641930104. Its totient is φ = 1336870041600.

The previous prime is 1538793120967. The next prime is 1538793121057. The reversal of 1538793121021 is 1201213978351.

It can be written as a sum of positive squares in 4 ways, for example, as 285277764996 + 1253515356025 = 534114^2 + 1119605^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1538793121021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1538793121081) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3481432180 + ... + 3481432621.

It is an arithmetic number, because the mean of its divisors is an integer number (219330241263).

Almost surely, 2^{1538793121021} is an apocalyptic number.

It is an amenable number.

1538793121021 is a deficient number, since it is larger than the sum of its proper divisors (215848809083).

1538793121021 is a wasteful number, since it uses less digits than its factorization.

1538793121021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6962864831.

The product of its (nonzero) digits is 90720, while the sum is 43.

The spelling of 1538793121021 in words is "one trillion, five hundred thirty-eight billion, seven hundred ninety-three million, one hundred twenty-one thousand, twenty-one".