20211221100251 has 2 divisors, whose sum is σ = 20211221100252. Its totient is φ = 20211221100250.

The previous prime is 20211221100211. The next prime is 20211221100277. The reversal of 20211221100251 is 15200112211202.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20211221100251 - 2²² = 20211216905947 is a prime.

It is not a weakly prime, because it can be changed into another prime (20211221100211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10105610550125 + 10105610550126.

It is an arithmetic number, because the mean of its divisors is an integer number (10105610550126).

Almost surely, 2^{20211221100251} is an apocalyptic number.

20211221100251 is a deficient number, since it is larger than the sum of its proper divisors (1).

20211221100251 is an equidigital number, since it uses as much as digits as its factorization.

20211221100251 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 160, while the sum is 20.

Adding to 20211221100251 its reverse (15200112211202), we get a palindrome (35411333311453).

The spelling of 20211221100251 in words is "twenty trillion, two hundred eleven billion, two hundred twenty-one million, one hundred thousand, two hundred fifty-one".