21881839 has 8 divisors (see below), whose sum is σ = 26479008. Its totient is φ = 17652480.

The previous prime is 21881831. The next prime is 21881851. The reversal of 21881839 is 93818812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21881839 - 2³ = 21881831 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21881831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 91822 + ... + 92059.

It is an arithmetic number, because the mean of its divisors is an integer number (3309876).

Almost surely, 2^21881839 is an apocalyptic number.

21881839 is a deficient number, since it is larger than the sum of its proper divisors (4597169).

21881839 is a wasteful number, since it uses less digits than its factorization.

21881839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 183905.

The product of its digits is 27648, while the sum is 40.

The square root of 21881839 is about 4677.8027961854. The cubic root of 21881839 is about 279.7013780594.

The spelling of 21881839 in words is "twenty-one million, eight hundred eighty-one thousand, eight hundred thirty-nine".