21388432859 has 2 divisors, whose sum is σ = 21388432860. Its totient is φ = 21388432858.

The previous prime is 21388432823. The next prime is 21388432873. The reversal of 21388432859 is 95823488312.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21388432859 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21388432859.

It is not a weakly prime, because it can be changed into another prime (21388431859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10694216429 + 10694216430.

It is an arithmetic number, because the mean of its divisors is an integer number (10694216430).

Almost surely, 2^21388432859 is an apocalyptic number.

21388432859 is a deficient number, since it is larger than the sum of its proper divisors (1).

21388432859 is an equidigital number, since it uses as much as digits as its factorization.

21388432859 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3317760, while the sum is 53.

The spelling of 21388432859 in words is "twenty-one billion, three hundred eighty-eight million, four hundred thirty-two thousand, eight hundred fifty-nine".