21003111979 has 2 divisors, whose sum is σ = 21003111980. Its totient is φ = 21003111978.

The previous prime is 21003111973. The next prime is 21003112061. The reversal of 21003111979 is 97911130012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21003111979 - 2¹⁹ = 21002587691 is a prime.

It is a super-2 number, since 2×21003111979² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21003111973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501555989 + 10501555990.

It is an arithmetic number, because the mean of its divisors is an integer number (10501555990).

Almost surely, 2^21003111979 is an apocalyptic number.

21003111979 is a deficient number, since it is larger than the sum of its proper divisors (1).

21003111979 is an equidigital number, since it uses as much as digits as its factorization.

21003111979 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3402, while the sum is 34.

The spelling of 21003111979 in words is "twenty-one billion, three million, one hundred eleven thousand, nine hundred seventy-nine".