999371729951921 has 32 divisors (see below), whose sum is σ = 1070411718528000. Its totient is φ = 929752095956992.

The previous prime is 999371729951897. The next prime is 999371729951951. The reversal of 999371729951921 is 129159927173999.

It is not a de Polignac number, because 999371729951921 - 2¹⁸ = 999371729689777 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 999371729951921.

It is not an unprimeable number, because it can be changed into a prime (999371729951951) 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, 10085547545 + ... + 10085646633.

It is an arithmetic number, because the mean of its divisors is an integer number (33450366204000).

Almost surely, 2^{999371729951921} is an apocalyptic number.

It is an amenable number.

999371729951921 is a deficient number, since it is larger than the sum of its proper divisors (71039988576079).

999371729951921 is a wasteful number, since it uses less digits than its factorization.

999371729951921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117601.

The product of its digits is 1562436540, while the sum is 83.

The spelling of 999371729951921 in words is "nine hundred ninety-nine trillion, three hundred seventy-one billion, seven hundred twenty-nine million, nine hundred fifty-one thousand, nine hundred twenty-one".