21284093939 has 2 divisors, whose sum is σ = 21284093940. Its totient is φ = 21284093938.

The previous prime is 21284093927. The next prime is 21284093983. The reversal of 21284093939 is 93939048212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21284093939 - 2³² = 16989126643 is a prime.

It is not a weakly prime, because it can be changed into another prime (21284090939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10642046969 + 10642046970.

It is an arithmetic number, because the mean of its divisors is an integer number (10642046970).

Almost surely, 2^21284093939 is an apocalyptic number.

21284093939 is a deficient number, since it is larger than the sum of its proper divisors (1).

21284093939 is an equidigital number, since it uses as much as digits as its factorization.

21284093939 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 839808, while the sum is 50.

The spelling of 21284093939 in words is "twenty-one billion, two hundred eighty-four million, ninety-three thousand, nine hundred thirty-nine".