21202122201977 has 2 divisors, whose sum is σ = 21202122201978. Its totient is φ = 21202122201976.

The previous prime is 21202122201947. The next prime is 21202122201979. The reversal of 21202122201977 is 77910222120212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15206108049001 + 5996014152976 = 3899501^2 + 2448676^2 .

It is a cyclic number.

It is not a de Polignac number, because 21202122201977 - 2²² = 21202118007673 is a prime.

Together with 21202122201979, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21202122201977.

It is not a weakly prime, because it can be changed into another prime (21202122201979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601061100988 + 10601061100989.

It is an arithmetic number, because the mean of its divisors is an integer number (10601061100989).

Almost surely, 2^{21202122201977} is an apocalyptic number.

It is an amenable number.

21202122201977 is a deficient number, since it is larger than the sum of its proper divisors (1).

21202122201977 is an equidigital number, since it uses as much as digits as its factorization.

21202122201977 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 28224, while the sum is 38.

The spelling of 21202122201977 in words is "twenty-one trillion, two hundred two billion, one hundred twenty-two million, two hundred one thousand, nine hundred seventy-seven".