21953125 has 16 divisors (see below), whose sum is σ = 27538992. Its totient is φ = 17500000.

The previous prime is 21953051. The next prime is 21953143. The reversal of 21953125 is 52135912.

It can be written as a sum of positive squares in 8 ways, for example, as 18515809 + 3437316 = 4303^2 + 1854^2 .

It is not a de Polignac number, because 21953125 - 2⁹ = 21952613 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 5.

It is a junction number, because it is equal to n+sod(n) for n = 21953093 and 21953102.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 77985 + ... + 78265.

It is an arithmetic number, because the mean of its divisors is an integer number (1721187).

Almost surely, 2^21953125 is an apocalyptic number.

21953125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21953125 is a deficient number, since it is larger than the sum of its proper divisors (5585867).

21953125 is an frugal number, since it uses more digits than its factorization.

21953125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 316 (or 286 counting only the distinct ones).

The product of its digits is 2700, while the sum is 28.

The square root of 21953125 is about 4685.4162034978. The cubic root of 21953125 is about 280.0047830816.

The spelling of 21953125 in words is "twenty-one million, nine hundred fifty-three thousand, one hundred twenty-five".