21745152 has 240 divisors, whose sum is σ = 76193040. Its totient is φ = 6082560.

The previous prime is 21745151. The next prime is 21745181. The reversal of 21745152 is 25154712.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21745151) 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, 1672698 + ... + 1672710.

It is an arithmetic number, because the mean of its divisors is an integer number (317471).

Almost surely, 2^21745152 is an apocalyptic number.

21745152 is a gapful number since it is divisible by the number (22) 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 21745152, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38096520).

21745152 is an abundant number, since it is smaller than the sum of its proper divisors (54447888).

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

21745152 is a wasteful number, since it uses less digits than its factorization.

21745152 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62 (or 29 counting only the distinct ones).

The product of its digits is 2800, while the sum is 27.

The square root of 21745152 is about 4663.1697374211. The cubic root of 21745152 is about 279.1177673715.

Adding to 21745152 its reverse (25154712), we get a palindrome (46899864).

It can be divided in two parts, 217 and 45152, that added together give a square (45369 = 213²).

The spelling of 21745152 in words is "twenty-one million, seven hundred forty-five thousand, one hundred fifty-two".