921666739231 has 16 divisors (see below), whose sum is σ = 1173993903360. Its totient is φ = 704396338560.

The previous prime is 921666739177. The next prime is 921666739243. The reversal of 921666739231 is 132937666129.

It is a cyclic number.

It is not a de Polignac number, because 921666739231 - 2¹⁹ = 921666214943 is a prime.

It is a super-3 number, since 3×921666739231³ (a number of 37 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (921666739261) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 203816125 + ... + 203820646.

It is an arithmetic number, because the mean of its divisors is an integer number (73374618960).

Almost surely, 2^921666739231 is an apocalyptic number.

921666739231 is a deficient number, since it is larger than the sum of its proper divisors (252327164129).

921666739231 is a wasteful number, since it uses less digits than its factorization.

921666739231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407636814.

The product of its digits is 4408992, while the sum is 55.

The spelling of 921666739231 in words is "nine hundred twenty-one billion, six hundred sixty-six million, seven hundred thirty-nine thousand, two hundred thirty-one".