21142405177 has 2 divisors, whose sum is σ = 21142405178. Its totient is φ = 21142405176.

The previous prime is 21142405171. The next prime is 21142405217. The reversal of 21142405177 is 77150424112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11080509696 + 10061895481 = 105264^2 + 100309^2 .

It is a cyclic number.

It is not a de Polignac number, because 21142405177 - 2⁷ = 21142405049 is a prime.

It is not a weakly prime, because it can be changed into another prime (21142405171) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10571202588 + 10571202589.

It is an arithmetic number, because the mean of its divisors is an integer number (10571202589).

Almost surely, 2^21142405177 is an apocalyptic number.

It is an amenable number.

21142405177 is a deficient number, since it is larger than the sum of its proper divisors (1).

21142405177 is an equidigital number, since it uses as much as digits as its factorization.

21142405177 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15680, while the sum is 34.

Adding to 21142405177 its reverse (77150424112), we get a palindrome (98292829289).

The spelling of 21142405177 in words is "twenty-one billion, one hundred forty-two million, four hundred five thousand, one hundred seventy-seven".