21121101173 has 2 divisors, whose sum is σ = 21121101174. Its totient is φ = 21121101172.

The previous prime is 21121101139. The next prime is 21121101247. The reversal of 21121101173 is 37110112112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14385123844 + 6735977329 = 119938^2 + 82073^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121101173 - 2⁶ = 21121101109 is a prime.

It is a super-2 number, since 2×21121101173² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21121101103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560550586 + 10560550587.

It is an arithmetic number, because the mean of its divisors is an integer number (10560550587).

Almost surely, 2^21121101173 is an apocalyptic number.

It is an amenable number.

21121101173 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121101173 is an equidigital number, since it uses as much as digits as its factorization.

21121101173 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 84, while the sum is 20.

Adding to 21121101173 its reverse (37110112112), we get a palindrome (58231213285).

The spelling of 21121101173 in words is "twenty-one billion, one hundred twenty-one million, one hundred one thousand, one hundred seventy-three".