21266506939 has 4 divisors (see below), whose sum is σ = 21267631000. Its totient is φ = 21265382880.

The previous prime is 21266506927. The next prime is 21266506991. The reversal of 21266506939 is 93960566212.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21266506939 - 2²⁹ = 20729636027 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21266506892 and 21266506901.

It is not an unprimeable number, because it can be changed into a prime (21266506739) 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 3 ways as a sum of consecutive naturals, for example, 533157 + ... + 571654.

It is an arithmetic number, because the mean of its divisors is an integer number (5316907750).

Almost surely, 2^21266506939 is an apocalyptic number.

21266506939 is a deficient number, since it is larger than the sum of its proper divisors (1124061).

21266506939 is a wasteful number, since it uses less digits than its factorization.

21266506939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1124060.

The product of its (nonzero) digits is 1049760, while the sum is 49.

The spelling of 21266506939 in words is "twenty-one billion, two hundred sixty-six million, five hundred six thousand, nine hundred thirty-nine".