21858925 has 24 divisors (see below), whose sum is σ = 29899872. Its totient is φ = 15720000.

The previous prime is 21858913. The next prime is 21858929. The reversal of 21858925 is 52985812.

It is not a de Polignac number, because 21858925 - 2¹³ = 21850733 is a prime.

It is a super-3 number, since 3×21858925³ (a number of 23 digits) contains 333 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21858929) 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 23 ways as a sum of consecutive naturals, for example, 27382 + ... + 28168.

It is an arithmetic number, because the mean of its divisors is an integer number (1245828).

Almost surely, 2^21858925 is an apocalyptic number.

21858925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21858925 is a deficient number, since it is larger than the sum of its proper divisors (8040947).

21858925 is a wasteful number, since it uses less digits than its factorization.

21858925 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 909 (or 904 counting only the distinct ones).

The product of its digits is 57600, while the sum is 40.

The square root of 21858925 is about 4675.3529278548. The cubic root of 21858925 is about 279.6037123527.

The spelling of 21858925 in words is "twenty-one million, eight hundred fifty-eight thousand, nine hundred twenty-five".