21045142177 has 2 divisors, whose sum is σ = 21045142178. Its totient is φ = 21045142176.

The previous prime is 21045142127. The next prime is 21045142219. The reversal of 21045142177 is 77124154012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14076398736 + 6968743441 = 118644^2 + 83479^2 .

It is a cyclic number.

It is not a de Polignac number, because 21045142177 - 2³¹ = 18897658529 is a prime.

It is not a weakly prime, because it can be changed into another prime (21045142127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10522571088 + 10522571089.

It is an arithmetic number, because the mean of its divisors is an integer number (10522571089).

Almost surely, 2^21045142177 is an apocalyptic number.

It is an amenable number.

21045142177 is a deficient number, since it is larger than the sum of its proper divisors (1).

21045142177 is an equidigital number, since it uses as much as digits as its factorization.

21045142177 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 21045142177 its reverse (77124154012), we get a palindrome (98169296189).

The spelling of 21045142177 in words is "twenty-one billion, forty-five million, one hundred forty-two thousand, one hundred seventy-seven".