21741439 has 4 divisors (see below), whose sum is σ = 22271760. Its totient is φ = 21211120.

The previous prime is 21741431. The next prime is 21741449. The reversal of 21741439 is 93414712.

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 21741439 - 2³ = 21741431 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21741439.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21741431) 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, 265099 + ... + 265180.

It is an arithmetic number, because the mean of its divisors is an integer number (5567940).

Almost surely, 2^21741439 is an apocalyptic number.

21741439 is a deficient number, since it is larger than the sum of its proper divisors (530321).

21741439 is an equidigital number, since it uses as much as digits as its factorization.

21741439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 530320.

The product of its digits is 6048, while the sum is 31.

The square root of 21741439 is about 4662.7716006684. The cubic root of 21741439 is about 279.1018799488.

The spelling of 21741439 in words is "twenty-one million, seven hundred forty-one thousand, four hundred thirty-nine".