21121106917747 has 2 divisors, whose sum is σ = 21121106917748. Its totient is φ = 21121106917746.

The previous prime is 21121106917717. The next prime is 21121106917777. The reversal of 21121106917747 is 74771960112112.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (21121106917717) and next prime (21121106917777).

It is a cyclic number.

It is not a de Polignac number, because 21121106917747 - 2¹⁵ = 21121106884979 is a prime.

It is a super-2 number, since 2×21121106917747² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21121106917747.

It is not a weakly prime, because it can be changed into another prime (21121106917717) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560553458873 + 10560553458874.

It is an arithmetic number, because the mean of its divisors is an integer number (10560553458874).

Almost surely, 2^{21121106917747} is an apocalyptic number.

21121106917747 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121106917747 is an equidigital number, since it uses as much as digits as its factorization.

21121106917747 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 296352, while the sum is 49.

The spelling of 21121106917747 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred six million, nine hundred seventeen thousand, seven hundred forty-seven".