21243937079 has 2 divisors, whose sum is σ = 21243937080. Its totient is φ = 21243937078.

The previous prime is 21243937061. The next prime is 21243937123. The reversal of 21243937079 is 97073934212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21243937079 - 2¹⁶ = 21243871543 is a prime.

It is a super-2 number, since 2×21243937079² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21243937019) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621968539 + 10621968540.

It is an arithmetic number, because the mean of its divisors is an integer number (10621968540).

Almost surely, 2^21243937079 is an apocalyptic number.

21243937079 is a deficient number, since it is larger than the sum of its proper divisors (1).

21243937079 is an equidigital number, since it uses as much as digits as its factorization.

21243937079 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 571536, while the sum is 47.

The spelling of 21243937079 in words is "twenty-one billion, two hundred forty-three million, nine hundred thirty-seven thousand, seventy-nine".