21240944879 has 24 divisors (see below), whose sum is σ = 27227440800. Its totient is φ = 16551353280.

The previous prime is 21240944783. The next prime is 21240944891. The reversal of 21240944879 is 97844904212.

It is not a de Polignac number, because 21240944879 - 2⁸ = 21240944623 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21240941879) 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 in 23 ways as a sum of consecutive naturals, for example, 214394 + ... + 297399.

It is an arithmetic number, because the mean of its divisors is an integer number (1134476700).

Almost surely, 2^21240944879 is an apocalyptic number.

21240944879 is a deficient number, since it is larger than the sum of its proper divisors (5986495921).

21240944879 is an equidigital number, since it uses as much as digits as its factorization.

21240944879 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 511836 (or 511811 counting only the distinct ones).

The product of its (nonzero) digits is 1161216, while the sum is 50.

The spelling of 21240944879 in words is "twenty-one billion, two hundred forty million, nine hundred forty-four thousand, eight hundred seventy-nine".