22021210101991 has 2 divisors, whose sum is σ = 22021210101992. Its totient is φ = 22021210101990.

The previous prime is 22021210101977. The next prime is 22021210102013. The reversal of 22021210101991 is 19910101212022.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 22021210101991 - 2²⁹ = 22020673231079 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22021210101901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11010605050995 + 11010605050996.

It is an arithmetic number, because the mean of its divisors is an integer number (11010605050996).

Almost surely, 2^{22021210101991} is an apocalyptic number.

22021210101991 is a deficient number, since it is larger than the sum of its proper divisors (1).

22021210101991 is an equidigital number, since it uses as much as digits as its factorization.

22021210101991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1296, while the sum is 31.

The spelling of 22021210101991 in words is "twenty-two trillion, twenty-one billion, two hundred ten million, one hundred one thousand, nine hundred ninety-one".