21011020010957 has 2 divisors, whose sum is σ = 21011020010958. Its totient is φ = 21011020010956.

The previous prime is 21011020010719. The next prime is 21011020011049. The reversal of 21011020010957 is 75901002011012.

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., 10950996574441 + 10060023436516 = 3309229^2 + 3171754^2 .

It is a cyclic number.

It is not a de Polignac number, because 21011020010957 - 2²⁴ = 21011003233741 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21011020040957) 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, 10505510005478 + 10505510005479.

It is an arithmetic number, because the mean of its divisors is an integer number (10505510005479).

Almost surely, 2^{21011020010957} is an apocalyptic number.

It is an amenable number.

21011020010957 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011020010957 is an equidigital number, since it uses as much as digits as its factorization.

21011020010957 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 29.

Adding to 21011020010957 its reverse (75901002011012), we get a palindrome (96912022021969).

The spelling of 21011020010957 in words is "twenty-one trillion, eleven billion, twenty million, ten thousand, nine hundred fifty-seven".