21755421445157 has 2 divisors, whose sum is σ = 21755421445158. Its totient is φ = 21755421445156.

The previous prime is 21755421445013. The next prime is 21755421445169. The reversal of 21755421445157 is 75154412455712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14889480798721 + 6865940646436 = 3858689^2 + 2620294^2 .

It is a cyclic number.

It is not a de Polignac number, because 21755421445157 - 2²⁰ = 21755420396581 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21755421445099 and 21755421445108.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21755421445957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10877710722578 + 10877710722579.

It is an arithmetic number, because the mean of its divisors is an integer number (10877710722579).

Almost surely, 2^{21755421445157} is an apocalyptic number.

It is an amenable number.

21755421445157 is a deficient number, since it is larger than the sum of its proper divisors (1).

21755421445157 is an equidigital number, since it uses as much as digits as its factorization.

21755421445157 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7840000, while the sum is 53.

The spelling of 21755421445157 in words is "twenty-one trillion, seven hundred fifty-five billion, four hundred twenty-one million, four hundred forty-five thousand, one hundred fifty-seven".