21879941 has 4 divisors (see below), whose sum is σ = 22052352. Its totient is φ = 21707532.

The previous prime is 21879929. The next prime is 21879943. The reversal of 21879941 is 14997812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21879941 - 2¹⁴ = 21863557 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21879943) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 86015 + ... + 86268.

It is an arithmetic number, because the mean of its divisors is an integer number (5513088).

Almost surely, 2^21879941 is an apocalyptic number.

It is an amenable number.

21879941 is a deficient number, since it is larger than the sum of its proper divisors (172411).

21879941 is a wasteful number, since it uses less digits than its factorization.

21879941 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172410.

The product of its digits is 36288, while the sum is 41.

The square root of 21879941 is about 4677.5999187618. The cubic root of 21879941 is about 279.6932908573.

The spelling of 21879941 in words is "twenty-one million, eight hundred seventy-nine thousand, nine hundred forty-one".