21873261 has 8 divisors (see below), whose sum is σ = 29437344. Its totient is φ = 14445680.

The previous prime is 21873251. The next prime is 21873277. The reversal of 21873261 is 16237812.

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 21873261 - 2⁹ = 21872749 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21873251) 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 7 ways as a sum of consecutive naturals, for example, 33750 + ... + 34391.

It is an arithmetic number, because the mean of its divisors is an integer number (3679668).

Almost surely, 2^21873261 is an apocalyptic number.

It is an amenable number.

21873261 is a deficient number, since it is larger than the sum of its proper divisors (7564083).

21873261 is a wasteful number, since it uses less digits than its factorization.

21873261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68251.

The product of its digits is 4032, while the sum is 30.

The square root of 21873261 is about 4676.8858228526. The cubic root of 21873261 is about 279.6648242761.

The spelling of 21873261 in words is "twenty-one million, eight hundred seventy-three thousand, two hundred sixty-one".