21625344 has 180 divisors, whose sum is σ = 70936866. Its totient is φ = 6303744.

The previous prime is 21625339. The next prime is 21625367. The reversal of 21625344 is 44352612.

21625344 is a `hidden beast` number, since 2 + 1 + 625 + 34 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 20793600 + 831744 = 4560^2 + 912^2 .

It is a super-3 number, since 3×21625344³ (a number of 23 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1138167 + ... + 1138185.

Almost surely, 2^21625344 is an apocalyptic number.

21625344 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21625344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35468433).

21625344 is an abundant number, since it is smaller than the sum of its proper divisors (49311522).

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

21625344 is a wasteful number, since it uses less digits than its factorization.

21625344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75 (or 37 counting only the distinct ones).

The product of its digits is 5760, while the sum is 27.

The square root of 21625344 is about 4650.3057963966. The cubic root of 21625344 is about 278.6042100616.

Adding to 21625344 its reverse (44352612), we get a palindrome (65977956).

The spelling of 21625344 in words is "twenty-one million, six hundred twenty-five thousand, three hundred forty-four".