1538123324521 has 9 divisors (see below), whose sum is σ = 1789255598871. Its totient is φ = 1318383979752.

The previous prime is 1538123324449. The next prime is 1538123324567. The reversal of 1538123324521 is 1254233218351.

The square root of 1538123324521 is 1240211.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 955398728025 + 582724596496 = 977445^2 + 763364^2 .

It is not a de Polignac number, because 1538123324521 - 2¹⁹ = 1538122800233 is a prime.

It is a super-2 number, since 2×1538123324521² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1538123322521) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 8592891 + ... + 8770063.

Almost surely, 2^{1538123324521} is an apocalyptic number.

1538123324521 is the 1240211-st square number.

1538123324521 is the 620106-th centered octagonal number.

It is an amenable number.

1538123324521 is a deficient number, since it is larger than the sum of its proper divisors (251132274350).

1538123324521 is an frugal number, since it uses more digits than its factorization.

1538123324521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 354360 (or 177180 counting only the distinct ones).

The product of its digits is 172800, while the sum is 40.

The spelling of 1538123324521 in words is "one trillion, five hundred thirty-eight billion, one hundred twenty-three million, three hundred twenty-four thousand, five hundred twenty-one".