21000555293 has 4 divisors (see below), whose sum is σ = 21008356188. Its totient is φ = 20992754400.

The previous prime is 21000555263. The next prime is 21000555307. The reversal of 21000555293 is 39255500012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3870457369 + 17130097924 = 62213^2 + 130882^2 .

It is a cyclic number.

It is not a de Polignac number, because 21000555293 - 2⁶ = 21000555229 is a prime.

It is a super-2 number, since 2×21000555293² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000555203) 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 3 ways as a sum of consecutive naturals, for example, 3896408 + ... + 3901793.

It is an arithmetic number, because the mean of its divisors is an integer number (5252089047).

Almost surely, 2^21000555293 is an apocalyptic number.

It is an amenable number.

21000555293 is a deficient number, since it is larger than the sum of its proper divisors (7800895).

21000555293 is an equidigital number, since it uses as much as digits as its factorization.

21000555293 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7800894.

The product of its (nonzero) digits is 13500, while the sum is 32.

The spelling of 21000555293 in words is "twenty-one billion, five hundred fifty-five thousand, two hundred ninety-three".