1538660541591 has 72 divisors (see below), whose sum is σ = 2530172290464. Its totient is φ = 898499036160.

The previous prime is 1538660541577. The next prime is 1538660541601. The reversal of 1538660541591 is 1951450668351.

It is a happy number.

1538660541591 is a `hidden beast` number, since 1 + 5 + 3 + 8 + 6 + 6 + 0 + 5 + 41 + 591 = 666.

It is not a de Polignac number, because 1538660541591 - 2³⁷ = 1401221588119 is a prime.

It is a super-2 number, since 2×1538660541591² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1538660540591) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1865881 + ... + 2561021.

It is an arithmetic number, because the mean of its divisors is an integer number (35141281812).

Almost surely, 2^{1538660541591} is an apocalyptic number.

1538660541591 is a deficient number, since it is larger than the sum of its proper divisors (991511748873).

1538660541591 is a wasteful number, since it uses less digits than its factorization.

1538660541591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 695241 (or 695221 counting only the distinct ones).

The product of its (nonzero) digits is 3888000, while the sum is 54.

The spelling of 1538660541591 in words is "one trillion, five hundred thirty-eight billion, six hundred sixty million, five hundred forty-one thousand, five hundred ninety-one".