21425008 has 80 divisors (see below), whose sum is σ = 49104000. Its totient is φ = 8951040.

The previous prime is 21425003. The next prime is 21425009. The reversal of 21425008 is 80052412.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a self number, because there is not a number n which added to its sum of digits gives 21425008.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21425003) 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 15 ways as a sum of consecutive naturals, for example, 143718 + ... + 143866.

It is an arithmetic number, because the mean of its divisors is an integer number (613800).

Almost surely, 2^21425008 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 21425008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24552000).

21425008 is an abundant number, since it is smaller than the sum of its proper divisors (27678992).

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

21425008 is a wasteful number, since it uses less digits than its factorization.

21425008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230 (or 224 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 22.

The square root of 21425008 is about 4628.7155885839. The cubic root of 21425008 is about 277.7412149328.

The spelling of 21425008 in words is "twenty-one million, four hundred twenty-five thousand, eight".