15680729721 has 16 divisors (see below), whose sum is σ = 21601893888. Its totient is φ = 10107312000.

The previous prime is 15680729717. The next prime is 15680729749. The reversal of 15680729721 is 12792708651.

It is not a de Polignac number, because 15680729721 - 2² = 15680729717 is a prime.

It is not an unprimeable number, because it can be changed into a prime (15680729321) 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 15 ways as a sum of consecutive naturals, for example, 25171 + ... + 178871.

It is an arithmetic number, because the mean of its divisors is an integer number (1350118368).

Almost surely, 2^15680729721 is an apocalyptic number.

It is an amenable number.

15680729721 is a deficient number, since it is larger than the sum of its proper divisors (5921164167).

15680729721 is a wasteful number, since it uses less digits than its factorization.

15680729721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154832.

The product of its (nonzero) digits is 423360, while the sum is 48.

The spelling of 15680729721 in words is "fifteen billion, six hundred eighty million, seven hundred twenty-nine thousand, seven hundred twenty-one".