21925040 has 40 divisors (see below), whose sum is σ = 51947568. Its totient is φ = 8602880.

The previous prime is 21925021. The next prime is 21925097. The reversal of 21925040 is 4052912.

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 21924997 and 21925015.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1655 + ... + 6825.

Almost surely, 2^21925040 is an apocalyptic number.

21925040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21925040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25973784).

21925040 is an abundant number, since it is smaller than the sum of its proper divisors (30022528).

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

21925040 is a wasteful number, since it uses less digits than its factorization.

21925040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5237 (or 5231 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 21925040 is about 4682.4181786765. The cubic root of 21925040 is about 279.8853271923.

Adding to 21925040 its reverse (4052912), we get a palindrome (25977952).

The spelling of 21925040 in words is "twenty-one million, nine hundred twenty-five thousand, forty".