21431411857 has 2 divisors, whose sum is σ = 21431411858. Its totient is φ = 21431411856.

The previous prime is 21431411851. The next prime is 21431411867. The reversal of 21431411857 is 75811413412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21341995921 + 89415936 = 146089^2 + 9456^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21431411857 is a prime.

It is not a weakly prime, because it can be changed into another prime (21431411851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10715705928 + 10715705929.

It is an arithmetic number, because the mean of its divisors is an integer number (10715705929).

Almost surely, 2^21431411857 is an apocalyptic number.

It is an amenable number.

21431411857 is a deficient number, since it is larger than the sum of its proper divisors (1).

21431411857 is an equidigital number, since it uses as much as digits as its factorization.

21431411857 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26880, while the sum is 37.

The spelling of 21431411857 in words is "twenty-one billion, four hundred thirty-one million, four hundred eleven thousand, eight hundred fifty-seven".