21023402171 has 2 divisors, whose sum is σ = 21023402172. Its totient is φ = 21023402170.

The previous prime is 21023402137. The next prime is 21023402201. The reversal of 21023402171 is 17120432012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21023402171 - 2³⁰ = 19949660347 is a prime.

It is not a weakly prime, because it can be changed into another prime (21023408171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10511701085 + 10511701086.

It is an arithmetic number, because the mean of its divisors is an integer number (10511701086).

Almost surely, 2^21023402171 is an apocalyptic number.

21023402171 is a deficient number, since it is larger than the sum of its proper divisors (1).

21023402171 is an equidigital number, since it uses as much as digits as its factorization.

21023402171 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 672, while the sum is 23.

Adding to 21023402171 its reverse (17120432012), we get a palindrome (38143834183).

The spelling of 21023402171 in words is "twenty-one billion, twenty-three million, four hundred two thousand, one hundred seventy-one".