21869039 has 2 divisors, whose sum is σ = 21869040. Its totient is φ = 21869038.

The previous prime is 21869033. The next prime is 21869041. The reversal of 21869039 is 93096812.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21869039 is a prime.

Together with 21869041, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21868993 and 21869011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21869033) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10934519 + 10934520.

It is an arithmetic number, because the mean of its divisors is an integer number (10934520).

Almost surely, 2^21869039 is an apocalyptic number.

21869039 is a deficient number, since it is larger than the sum of its proper divisors (1).

21869039 is an equidigital number, since it uses as much as digits as its factorization.

21869039 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 21869039 is about 4676.4344323427. The cubic root of 21869039 is about 279.6468293847.

The spelling of 21869039 in words is "twenty-one million, eight hundred sixty-nine thousand, thirty-nine".