21121311261606 has 16 divisors (see below), whose sum is σ = 42242667681648. Its totient is φ = 7040429560800.

The previous prime is 21121311261563. The next prime is 21121311261637. The reversal of 21121311261606 is 60616211312112.

It is a super-2 number, since 2×21121311261606² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 9424896 + ... + 11448636.

It is an arithmetic number, because the mean of its divisors is an integer number (2640166730103).

Almost surely, 2^{21121311261606} is an apocalyptic number.

21121311261606 is an abundant number, since it is smaller than the sum of its proper divisors (21121356420042).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21121311261606 is a wasteful number, since it uses less digits than its factorization.

21121311261606 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3763207.

The product of its (nonzero) digits is 5184, while the sum is 33.

Adding to 21121311261606 its reverse (60616211312112), we get a palindrome (81737522573718).

The spelling of 21121311261606 in words is "twenty-one trillion, one hundred twenty-one billion, three hundred eleven million, two hundred sixty-one thousand, six hundred six".