21100123357 has 2 divisors, whose sum is σ = 21100123358. Its totient is φ = 21100123356.

The previous prime is 21100123283. The next prime is 21100123379. The reversal of 21100123357 is 75332100112.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20512254841 + 587868516 = 143221^2 + 24246^2 .

It is a cyclic number.

It is not a de Polignac number, because 21100123357 - 2¹¹ = 21100121309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21100129357) by changing a digit.

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 as a sum of consecutive naturals, namely, 10550061678 + 10550061679.

It is an arithmetic number, because the mean of its divisors is an integer number (10550061679).

Almost surely, 2^21100123357 is an apocalyptic number.

It is an amenable number.

21100123357 is a deficient number, since it is larger than the sum of its proper divisors (1).

21100123357 is an equidigital number, since it uses as much as digits as its factorization.

21100123357 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1260, while the sum is 25.

Adding to 21100123357 its reverse (75332100112), we get a palindrome (96432223469).

The spelling of 21100123357 in words is "twenty-one billion, one hundred million, one hundred twenty-three thousand, three hundred fifty-seven".