21953020 has 12 divisors (see below), whose sum is σ = 46101384. Its totient is φ = 8781200.

The previous prime is 21953011. The next prime is 21953033. The reversal of 21953020 is 2035912.

It is a junction number, because it is equal to n+sod(n) for n = 21952982 and 21953000.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 548806 + ... + 548845.

It is an arithmetic number, because the mean of its divisors is an integer number (3841782).

Almost surely, 2^21953020 is an apocalyptic number.

21953020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21953020 is an abundant number, since it is smaller than the sum of its proper divisors (24148364).

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

21953020 is a wasteful number, since it uses less digits than its factorization.

21953020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1097660 (or 1097658 counting only the distinct ones).

The product of its (nonzero) digits is 540, while the sum is 22.

The square root of 21953020 is about 4685.4049985033. The cubic root of 21953020 is about 280.0043366675.

Adding to 21953020 its reverse (2035912), we get a palindrome (23988932).

The spelling of 21953020 in words is "twenty-one million, nine hundred fifty-three thousand, twenty".