15721868535513 has 32 divisors (see below), whose sum is σ = 25218606090240. Its totient is φ = 8510893896960.

The previous prime is 15721868535409. The next prime is 15721868535521. The reversal of 15721868535513 is 31553586812751.

It is a happy number.

It is not a de Polignac number, because 15721868535513 - 2¹⁷ = 15721868404441 is a prime.

It is not an unprimeable number, because it can be changed into a prime (15721868535713) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18157153 + ... + 19003313.

It is an arithmetic number, because the mean of its divisors is an integer number (788081440320).

Almost surely, 2^{15721868535513} is an apocalyptic number.

It is an amenable number.

15721868535513 is a deficient number, since it is larger than the sum of its proper divisors (9496737554727).

15721868535513 is a wasteful number, since it uses less digits than its factorization.

15721868535513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 892757.

The product of its digits is 30240000, while the sum is 60.

The spelling of 15721868535513 in words is "fifteen trillion, seven hundred twenty-one billion, eight hundred sixty-eight million, five hundred thirty-five thousand, five hundred thirteen".