9921952881 has 9 divisors (see below), whose sum is σ = 14332141369. Its totient is φ = 6614436036.

The previous prime is 9921952867. The next prime is 9921952979. The reversal of 9921952881 is 1882591299.

The square root of 9921952881 is 99609.

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

9921952881 is a `hidden beast` number, since 99 + 21 + 9 + 528 + 8 + 1 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 9921952881 - 2¹¹ = 9921950833 is a prime.

It is a super-2 number, since 2×9921952881² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9921952841) 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 8 ways as a sum of consecutive naturals, for example, 282226 + ... + 315428.

Almost surely, 2^9921952881 is an apocalyptic number.

9921952881 is the 99609-th square number.

9921952881 is the 49805-th centered octagonal number.

It is an amenable number.

9921952881 is a deficient number, since it is larger than the sum of its proper divisors (4410188488).

9921952881 is an frugal number, since it uses more digits than its factorization.

9921952881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66412 (or 33206 counting only the distinct ones).

The product of its digits is 933120, while the sum is 54.

The cubic root of 9921952881 is about 2148.8151308753.

It can be divided in two parts, 99219 and 52881, that added together give a square (152100 = 390²).

The spelling of 9921952881 in words is "nine billion, nine hundred twenty-one million, nine hundred fifty-two thousand, eight hundred eighty-one".