21101579123 has 2 divisors, whose sum is σ = 21101579124. Its totient is φ = 21101579122.

The previous prime is 21101579117. The next prime is 21101579153. The reversal of 21101579123 is 32197510112.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21101579123 - 2⁸ = 21101578867 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21101579123.

It is not a weakly prime, because it can be changed into another prime (21101579153) 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, 10550789561 + 10550789562.

It is an arithmetic number, because the mean of its divisors is an integer number (10550789562).

Almost surely, 2^21101579123 is an apocalyptic number.

21101579123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101579123 is an equidigital number, since it uses as much as digits as its factorization.

21101579123 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3780, while the sum is 32.

The spelling of 21101579123 in words is "twenty-one billion, one hundred one million, five hundred seventy-nine thousand, one hundred twenty-three".