21000938458385 has 4 divisors (see below), whose sum is σ = 25201126150068. Its totient is φ = 16800750766704.

The previous prime is 21000938458369. The next prime is 21000938458387. The reversal of 21000938458385 is 58385483900012.

It is a happy number.

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 11695900685329 + 9305037773056 = 3419927^2 + 3050416^2 .

It is a cyclic number.

It is not a de Polignac number, because 21000938458385 - 2⁴ = 21000938458369 is a prime.

It is a super-2 number, since 2×21000938458385² (a number of 27 digits) contains 22 as substring.

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 21000938458385.

It is not an unprimeable number, because it can be changed into a prime (21000938458387) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2100093845834 + ... + 2100093845843.

It is an arithmetic number, because the mean of its divisors is an integer number (6300281537517).

Almost surely, 2^{21000938458385} is an apocalyptic number.

It is an amenable number.

21000938458385 is a deficient number, since it is larger than the sum of its proper divisors (4200187691683).

21000938458385 is an equidigital number, since it uses as much as digits as its factorization.

21000938458385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4200187691682.

The product of its (nonzero) digits is 8294400, while the sum is 56.

The spelling of 21000938458385 in words is "twenty-one trillion, nine hundred thirty-eight million, four hundred fifty-eight thousand, three hundred eighty-five".