21431142077 has 2 divisors, whose sum is σ = 21431142078. Its totient is φ = 21431142076.

The previous prime is 21431142059. The next prime is 21431142121. The reversal of 21431142077 is 77024113412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13626126361 + 7805015716 = 116731^2 + 88346^2 .

It is a cyclic number.

It is not a de Polignac number, because 21431142077 - 2²⁰ = 21430093501 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21431142977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10715571038 + 10715571039.

It is an arithmetic number, because the mean of its divisors is an integer number (10715571039).

Almost surely, 2^21431142077 is an apocalyptic number.

It is an amenable number.

21431142077 is a deficient number, since it is larger than the sum of its proper divisors (1).

21431142077 is an equidigital number, since it uses as much as digits as its factorization.

21431142077 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9408, while the sum is 32.

Adding to 21431142077 its reverse (77024113412), we get a palindrome (98455255489).

The spelling of 21431142077 in words is "twenty-one billion, four hundred thirty-one million, one hundred forty-two thousand, seventy-seven".