21738625 has 8 divisors (see below), whose sum is σ = 27129960. Its totient is φ = 17390800.

The previous prime is 21738623. The next prime is 21738637. The reversal of 21738625 is 52683712.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 5157441 + 16581184 = 2271^2 + 4072^2 .

It is not a de Polignac number, because 21738625 - 2¹ = 21738623 is a prime.

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21738623) 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 7 ways as a sum of consecutive naturals, for example, 86830 + ... + 87079.

It is an arithmetic number, because the mean of its divisors is an integer number (3391245).

Almost surely, 2^21738625 is an apocalyptic number.

21738625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21738625 is a deficient number, since it is larger than the sum of its proper divisors (5391335).

21738625 is an equidigital number, since it uses as much as digits as its factorization.

21738625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173924 (or 173914 counting only the distinct ones).

The product of its digits is 20160, while the sum is 34.

The square root of 21738625 is about 4662.4698390445. The cubic root of 21738625 is about 279.0898380201.

The spelling of 21738625 in words is "twenty-one million, seven hundred thirty-eight thousand, six hundred twenty-five".