1538197738081 has 3 divisors (see below), whose sum is σ = 1538198978323. Its totient is φ = 1538196497840.

The previous prime is 1538197738061. The next prime is 1538197738097. The reversal of 1538197738081 is 1808377918351.

The square root of 1538197738081 is 1240241.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 463160552481 + 1075037185600 = 680559^2 + 1036840^2 .

It is not a de Polignac number, because 1538197738081 - 2⁷ = 1538197737953 is a prime.

It is a super-2 number, since 2×1538197738081² (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 (1538197738061) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 620121 + ... + 1860361.

Almost surely, 2^{1538197738081} is an apocalyptic number.

1538197738081 is the 1240241-st square number.

1538197738081 is the 620121-st centered octagonal number.

It is an amenable number.

1538197738081 is a deficient number, since it is larger than the sum of its proper divisors (1240242).

1538197738081 is an frugal number, since it uses more digits than its factorization.

1538197738081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2480482 (or 1240241 counting only the distinct ones).

The product of its (nonzero) digits is 10160640, while the sum is 61.

The spelling of 1538197738081 in words is "one trillion, five hundred thirty-eight billion, one hundred ninety-seven million, seven hundred thirty-eight thousand, eighty-one".