21795540 has 48 divisors (see below), whose sum is σ = 65724288. Its totient is φ = 5364864.

The previous prime is 21795523. The next prime is 21795541. The reversal of 21795540 is 4559712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21795541) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 13192 + ... + 14751.

It is an arithmetic number, because the mean of its divisors is an integer number (1369256).

Almost surely, 2^21795540 is an apocalyptic number.

21795540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21795540 is an abundant number, since it is smaller than the sum of its proper divisors (43928748).

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

21795540 is a wasteful number, since it uses less digits than its factorization.

21795540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27968 (or 27966 counting only the distinct ones).

The product of its (nonzero) digits is 12600, while the sum is 33.

The square root of 21795540 is about 4668.5693740160. The cubic root of 21795540 is about 279.3331921984. Note that the first 3 decimals are identical.

The spelling of 21795540 in words is "twenty-one million, seven hundred ninety-five thousand, five hundred forty".