21240431039 has 2 divisors, whose sum is σ = 21240431040. Its totient is φ = 21240431038.

The previous prime is 21240430987. The next prime is 21240431063. The reversal of 21240431039 is 93013404212.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21240431039 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21240431539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10620215519 + 10620215520.

It is an arithmetic number, because the mean of its divisors is an integer number (10620215520).

Almost surely, 2^21240431039 is an apocalyptic number.

21240431039 is a deficient number, since it is larger than the sum of its proper divisors (1).

21240431039 is an equidigital number, since it uses as much as digits as its factorization.

21240431039 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 29.

The spelling of 21240431039 in words is "twenty-one billion, two hundred forty million, four hundred thirty-one thousand, thirty-nine".