2015681544009 has 27 divisors (see below), whose sum is σ = 3386943576237. Its totient is φ = 1151800988184.

The previous prime is 2015681543963. The next prime is 2015681544017. The reversal of 2015681544009 is 9004451865102.

The square root of 2015681544009 is 1419747.

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

2015681544009 is a `hidden beast` number, since 20 + 1 + 5 + 6 + 81 + 544 + 0 + 0 + 9 = 666.

It is not a de Polignac number, because 2015681544009 - 2¹¹ = 2015681541961 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2015681544029) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 29780884 + ... + 29848490.

Almost surely, 2^{2015681544009} is an apocalyptic number.

2015681544009 is the 1419747-th square number.

2015681544009 is the 709874-th centered octagonal number.

It is an amenable number.

2015681544009 is a deficient number, since it is larger than the sum of its proper divisors (1371262032228).

2015681544009 is an frugal number, since it uses more digits than its factorization.

2015681544009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135234 (or 67617 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 45.

The spelling of 2015681544009 in words is "two trillion, fifteen billion, six hundred eighty-one million, five hundred forty-four thousand, nine".