21019812479 has 2 divisors, whose sum is σ = 21019812480. Its totient is φ = 21019812478.

The previous prime is 21019812467. The next prime is 21019812497. The reversal of 21019812479 is 97421891012.

It is a happy number.

Together with next prime (21019812497) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21019812479 - 2³² = 16724845183 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21019812419) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10509906239 + 10509906240.

It is an arithmetic number, because the mean of its divisors is an integer number (10509906240).

Almost surely, 2^21019812479 is an apocalyptic number.

21019812479 is a deficient number, since it is larger than the sum of its proper divisors (1).

21019812479 is an equidigital number, since it uses as much as digits as its factorization.

21019812479 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72576, while the sum is 44.

The spelling of 21019812479 in words is "twenty-one billion, nineteen million, eight hundred twelve thousand, four hundred seventy-nine".