21028345223377 has 2 divisors, whose sum is σ = 21028345223378. Its totient is φ = 21028345223376.

The previous prime is 21028345223321. The next prime is 21028345223429. The reversal of 21028345223377 is 77332254382012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21028314320896 + 30902481 = 4585664^2 + 5559^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21028345223377 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21028345223377.

It is not a weakly prime, because it can be changed into another prime (21028345227377) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10514172611688 + 10514172611689.

It is an arithmetic number, because the mean of its divisors is an integer number (10514172611689).

Almost surely, 2^{21028345223377} is an apocalyptic number.

It is an amenable number.

21028345223377 is a deficient number, since it is larger than the sum of its proper divisors (1).

21028345223377 is an equidigital number, since it uses as much as digits as its factorization.

21028345223377 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3386880, while the sum is 49.

The spelling of 21028345223377 in words is "twenty-one trillion, twenty-eight billion, three hundred forty-five million, two hundred twenty-three thousand, three hundred seventy-seven".