21875311 has 4 divisors (see below), whose sum is σ = 23162112. Its totient is φ = 20588512.

The previous prime is 21875303. The next prime is 21875333. The reversal of 21875311 is 11357812.

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 21875311 - 2³ = 21875303 is a prime.

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 21875311.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21875611) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 643375 + ... + 643408.

It is an arithmetic number, because the mean of its divisors is an integer number (5790528).

Almost surely, 2^21875311 is an apocalyptic number.

21875311 is a deficient number, since it is larger than the sum of its proper divisors (1286801).

21875311 is a wasteful number, since it uses less digits than its factorization.

21875311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1286800.

The product of its digits is 1680, while the sum is 28.

The square root of 21875311 is about 4677.1049806478. The cubic root of 21875311 is about 279.6735608941.

The spelling of 21875311 in words is "twenty-one million, eight hundred seventy-five thousand, three hundred eleven".