21858804 has 108 divisors (see below), whose sum is σ = 64366848. Its totient is φ = 6201600.

The previous prime is 21858803. The next prime is 21858857. The reversal of 21858804 is 40885812.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21858803) 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 35 ways as a sum of consecutive naturals, for example, 114349 + ... + 114539.

Almost surely, 2^21858804 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21858804, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32183424).

21858804 is an abundant number, since it is smaller than the sum of its proper divisors (42508044).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21858804 is a wasteful number, since it uses less digits than its factorization.

21858804 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 246 (or 224 counting only the distinct ones).

The product of its (nonzero) digits is 20480, while the sum is 36.

The square root of 21858804 is about 4675.3399876373. The cubic root of 21858804 is about 279.6031964367.

The spelling of 21858804 in words is "twenty-one million, eight hundred fifty-eight thousand, eight hundred four".