21085664132 has 24 divisors (see below), whose sum is σ = 39874021656. Its totient is φ = 9698623488.

The previous prime is 21085664129. The next prime is 21085664137. The reversal of 21085664132 is 23146658012.

It can be written as a sum of positive squares in 4 ways, for example, as 11677828096 + 9407836036 = 108064^2 + 96994^2 .

It is a super-2 number, since 2×21085664132² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21085664137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 676733 + ... + 707204.

It is an arithmetic number, because the mean of its divisors is an integer number (1661417569).

Almost surely, 2^21085664132 is an apocalyptic number.

It is an amenable number.

21085664132 is a deficient number, since it is larger than the sum of its proper divisors (18788357524).

21085664132 is a wasteful number, since it uses less digits than its factorization.

21085664132 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1384247 (or 1384245 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 38.

The spelling of 21085664132 in words is "twenty-one billion, eighty-five million, six hundred sixty-four thousand, one hundred thirty-two".