21050445257 has 2 divisors, whose sum is σ = 21050445258. Its totient is φ = 21050445256.

The previous prime is 21050445223. The next prime is 21050445271. The reversal of 21050445257 is 75254405012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17670650761 + 3379794496 = 132931^2 + 58136^2 .

It is a cyclic number.

It is not a de Polignac number, because 21050445257 - 2⁶ = 21050445193 is a prime.

It is not a weakly prime, because it can be changed into another prime (21050465257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10525222628 + 10525222629.

It is an arithmetic number, because the mean of its divisors is an integer number (10525222629).

Almost surely, 2^21050445257 is an apocalyptic number.

It is an amenable number.

21050445257 is a deficient number, since it is larger than the sum of its proper divisors (1).

21050445257 is an equidigital number, since it uses as much as digits as its factorization.

21050445257 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 56000, while the sum is 35.

The spelling of 21050445257 in words is "twenty-one billion, fifty million, four hundred forty-five thousand, two hundred fifty-seven".