21748525 has 24 divisors (see below), whose sum is σ = 28986984. Its totient is φ = 16128000.

The previous prime is 21748523. The next prime is 21748537. The reversal of 21748525 is 52584712.

It is a happy number.

It can be written as a sum of positive squares in 12 ways, for example, as 487204 + 21261321 = 698^2 + 4611^2 .

It is not a de Polignac number, because 21748525 - 2¹ = 21748523 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21748523) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 30675 + ... + 31375.

It is an arithmetic number, because the mean of its divisors is an integer number (1207791).

Almost surely, 2^21748525 is an apocalyptic number.

21748525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21748525 is a deficient number, since it is larger than the sum of its proper divisors (7238459).

21748525 is a wasteful number, since it uses less digits than its factorization.

21748525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 801 (or 796 counting only the distinct ones).

The product of its digits is 22400, while the sum is 34.

The square root of 21748525 is about 4663.5313872644. The cubic root of 21748525 is about 279.1321984127.

The spelling of 21748525 in words is "twenty-one million, seven hundred forty-eight thousand, five hundred twenty-five".