21266839 has 6 divisors (see below), whose sum is σ = 23376080. Its totient is φ = 19333380.

The previous prime is 21266807. The next prime is 21266849. The reversal of 21266839 is 93866212.

It is not a de Polignac number, because 21266839 - 2⁵ = 21266807 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21266798 and 21266807.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21266849) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 87759 + ... + 88000.

Almost surely, 2^21266839 is an apocalyptic number.

21266839 is a deficient number, since it is larger than the sum of its proper divisors (2109241).

21266839 is a wasteful number, since it uses less digits than its factorization.

21266839 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 175781 (or 175770 counting only the distinct ones).

The product of its digits is 31104, while the sum is 37.

The square root of 21266839 is about 4611.5983129496. The cubic root of 21266839 is about 277.0560561134.

The spelling of 21266839 in words is "twenty-one million, two hundred sixty-six thousand, eight hundred thirty-nine".