21011300122957 has 2 divisors, whose sum is σ = 21011300122958. Its totient is φ = 21011300122956.

The previous prime is 21011300122951. The next prime is 21011300123029. The reversal of 21011300122957 is 75922100311012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17361438890436 + 3649861232521 = 4166706^2 + 1910461^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21011300122957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21011300122951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505650061478 + 10505650061479.

It is an arithmetic number, because the mean of its divisors is an integer number (10505650061479).

Almost surely, 2^{21011300122957} is an apocalyptic number.

It is an amenable number.

21011300122957 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011300122957 is an equidigital number, since it uses as much as digits as its factorization.

21011300122957 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7560, while the sum is 34.

Adding to 21011300122957 its reverse (75922100311012), we get a palindrome (96933400433969).

The spelling of 21011300122957 in words is "twenty-one trillion, eleven billion, three hundred million, one hundred twenty-two thousand, nine hundred fifty-seven".