115539487921 has 27 divisors (see below), whose sum is σ = 137576367873. Its totient is φ = 96915424320.

The previous prime is 115539487897. The next prime is 115539487927. The reversal of 115539487921 is 129784935511.

The square root of 115539487921 is 339911.

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

It can be written as a sum of positive squares in 4 ways, for example, as 26150447521 + 89389040400 = 161711^2 + 298980^2 .

It is not a de Polignac number, because 115539487921 - 2²⁵ = 115505933489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (115539487927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 48606085 + ... + 48608461.

Almost surely, 2^115539487921 is an apocalyptic number.

115539487921 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

115539487921 is the 339911-st square number.

115539487921 is the 169956-th centered octagonal number.

It is an amenable number.

115539487921 is a deficient number, since it is larger than the sum of its proper divisors (22036879952).

115539487921 is an frugal number, since it uses more digits than its factorization.

115539487921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4802 (or 2401 counting only the distinct ones).

The product of its digits is 2721600, while the sum is 55.

The spelling of 115539487921 in words is "one hundred fifteen billion, five hundred thirty-nine million, four hundred eighty-seven thousand, nine hundred twenty-one".