21142111477 has 2 divisors, whose sum is σ = 21142111478. Its totient is φ = 21142111476.

The previous prime is 21142111423. The next prime is 21142111493. The reversal of 21142111477 is 77411124112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20861180356 + 280931121 = 144434^2 + 16761^2 .

It is a cyclic number.

It is not a de Polignac number, because 21142111477 - 2⁷ = 21142111349 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21142112477) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10571055738 + 10571055739.

It is an arithmetic number, because the mean of its divisors is an integer number (10571055739).

Almost surely, 2^21142111477 is an apocalyptic number.

It is an amenable number.

21142111477 is a deficient number, since it is larger than the sum of its proper divisors (1).

21142111477 is an equidigital number, since it uses as much as digits as its factorization.

21142111477 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3136, while the sum is 31.

Adding to 21142111477 its reverse (77411124112), we get a palindrome (98553235589).

The spelling of 21142111477 in words is "twenty-one billion, one hundred forty-two million, one hundred eleven thousand, four hundred seventy-seven".