21026013607873 has 4 divisors (see below), whose sum is σ = 21026057353668. Its totient is φ = 21025969862080.

The previous prime is 21026013607771. The next prime is 21026013607883. The reversal of 21026013607873 is 37870631062012.

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 4698975314944 + 16327038292929 = 2167712^2 + 4040673^2 .

It is a cyclic number.

It is not a de Polignac number, because 21026013607873 - 2¹⁷ = 21026013476801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21026013607883) 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, 21143836 + ... + 22115917.

It is an arithmetic number, because the mean of its divisors is an integer number (5256514338417).

Almost surely, 2^{21026013607873} is an apocalyptic number.

It is an amenable number.

21026013607873 is a deficient number, since it is larger than the sum of its proper divisors (43745795).

21026013607873 is an equidigital number, since it uses as much as digits as its factorization.

21026013607873 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43745794.

The product of its (nonzero) digits is 508032, while the sum is 46.

Adding to 21026013607873 its reverse (37870631062012), we get a palindrome (58896644669885).

The spelling of 21026013607873 in words is "twenty-one trillion, twenty-six billion, thirteen million, six hundred seven thousand, eight hundred seventy-three".