21011218025797 has 2 divisors, whose sum is σ = 21011218025798. Its totient is φ = 21011218025796.

The previous prime is 21011218025783. The next prime is 21011218025801. The reversal of 21011218025797 is 79752081211012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19791163023076 + 1220055002721 = 4448726^2 + 1104561^2 .

It is a cyclic number.

It is not a de Polignac number, because 21011218025797 - 2⁷ = 21011218025669 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21011218025737) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505609012898 + 10505609012899.

It is an arithmetic number, because the mean of its divisors is an integer number (10505609012899).

Almost surely, 2^{21011218025797} is an apocalyptic number.

It is an amenable number.

21011218025797 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011218025797 is an equidigital number, since it uses as much as digits as its factorization.

21011218025797 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 141120, while the sum is 46.

The spelling of 21011218025797 in words is "twenty-one trillion, eleven billion, two hundred eighteen million, twenty-five thousand, seven hundred ninety-seven".