21026511505606 has 4 divisors (see below), whose sum is σ = 31539767258412. Its totient is φ = 10513255752802.

The previous prime is 21026511505603. The next prime is 21026511505621. The reversal of 21026511505606 is 60650511562012.

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

It is a super-2 number, since 2×21026511505606² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21026511505603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5256627876400 + ... + 5256627876403.

It is an arithmetic number, because the mean of its divisors is an integer number (7884941814603).

Almost surely, 2^{21026511505606} is an apocalyptic number.

21026511505606 is a deficient number, since it is larger than the sum of its proper divisors (10513255752806).

21026511505606 is a wasteful number, since it uses less digits than its factorization.

21026511505606 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10513255752805.

The product of its (nonzero) digits is 108000, while the sum is 40.

The spelling of 21026511505606 in words is "twenty-one trillion, twenty-six billion, five hundred eleven million, five hundred five thousand, six hundred six".