21801875 has 10 divisors (see below), whose sum is σ = 27244404. Its totient is φ = 17441000.

The previous prime is 21801869. The next prime is 21801877. The reversal of 21801875 is 57810812.

It is a happy number.

It is not a de Polignac number, because 21801875 - 2⁶ = 21801811 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21801877) 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 9 ways as a sum of consecutive naturals, for example, 16817 + ... + 18066.

Almost surely, 2^21801875 is an apocalyptic number.

21801875 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21801875 is a deficient number, since it is larger than the sum of its proper divisors (5442529).

21801875 is an frugal number, since it uses more digits than its factorization.

21801875 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34903 (or 34888 counting only the distinct ones).

The product of its (nonzero) digits is 4480, while the sum is 32.

The square root of 21801875 is about 4669.2477980934. The cubic root of 21801875 is about 279.3602528471.

The spelling of 21801875 in words is "twenty-one million, eight hundred one thousand, eight hundred seventy-five".