21550875 has 32 divisors (see below), whose sum is σ = 36279360. Its totient is φ = 11360000.

The previous prime is 21550861. The next prime is 21550891. The reversal of 21550875 is 57805512.

It is a happy number.

It is not a de Polignac number, because 21550875 - 2⁶ = 21550811 is a prime.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 37591 + ... + 38159.

It is an arithmetic number, because the mean of its divisors is an integer number (1133730).

Almost surely, 2^21550875 is an apocalyptic number.

21550875 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21550875 is a deficient number, since it is larger than the sum of its proper divisors (14728485).

21550875 is a wasteful number, since it uses less digits than its factorization.

21550875 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 688 (or 678 counting only the distinct ones).

The product of its (nonzero) digits is 14000, while the sum is 33.

The square root of 21550875 is about 4642.2919985714. The cubic root of 21550875 is about 278.2840419324.

The spelling of 21550875 in words is "twenty-one million, five hundred fifty thousand, eight hundred seventy-five".