21100002221257 has 2 divisors, whose sum is σ = 21100002221258. Its totient is φ = 21100002221256.

The previous prime is 21100002221201. The next prime is 21100002221269. The reversal of 21100002221257 is 75212220000112.

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., 12560141552841 + 8539860668416 = 3544029^2 + 2922304^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21100002221257 is a prime.

It is a super-3 number, since 3×21100002221257³ (a number of 41 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (21100002221057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550001110628 + 10550001110629.

It is an arithmetic number, because the mean of its divisors is an integer number (10550001110629).

Almost surely, 2^{21100002221257} is an apocalyptic number.

It is an amenable number.

21100002221257 is a deficient number, since it is larger than the sum of its proper divisors (1).

21100002221257 is an equidigital number, since it uses as much as digits as its factorization.

21100002221257 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1120, while the sum is 25.

Adding to 21100002221257 its reverse (75212220000112), we get a palindrome (96312222221369).

The spelling of 21100002221257 in words is "twenty-one trillion, one hundred billion, two million, two hundred twenty-one thousand, two hundred fifty-seven".