15639960558121 has 9 divisors (see below), whose sum is σ = 15659358839383. Its totient is φ = 15620586291760.

The previous prime is 15639960558119. The next prime is 15639960558133. The reversal of 15639960558121 is 12185506993651.

The square root of 15639960558121 is 3954739.

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

15639960558121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 9856705132521 + 5783255425600 = 3139539^2 + 2404840^2 .

It is not a de Polignac number, because 15639960558121 - 2¹ = 15639960558119 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 15639960558121.

It is not an unprimeable number, because it can be changed into a prime (15639960558721) 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, 4029877101 + ... + 4029880981.

Almost surely, 2^{15639960558121} is an apocalyptic number.

15639960558121 is the 3954739-th square number.

15639960558121 is the 1977370-th centered octagonal number.

It is an amenable number.

15639960558121 is a deficient number, since it is larger than the sum of its proper divisors (19398281262).

15639960558121 is an frugal number, since it uses more digits than its factorization.

15639960558121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9800 (or 4900 counting only the distinct ones).

The product of its (nonzero) digits is 17496000, while the sum is 61.

The spelling of 15639960558121 in words is "fifteen trillion, six hundred thirty-nine billion, nine hundred sixty million, five hundred fifty-eight thousand, one hundred twenty-one".