21745153 has 8 divisors (see below), whose sum is σ = 21983400. Its totient is φ = 21508608.

The previous prime is 21745151. The next prime is 21745181. The reversal of 21745153 is 35154712.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 2455489 + 19289664 = 1567^2 + 4392^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21745153 - 2¹ = 21745151 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21745151) 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, 61425 + ... + 61777.

It is an arithmetic number, because the mean of its divisors is an integer number (2747925).

Almost surely, 2^21745153 is an apocalyptic number.

It is an amenable number.

21745153 is a deficient number, since it is larger than the sum of its proper divisors (238247).

21745153 is a wasteful number, since it uses less digits than its factorization.

21745153 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 851.

The product of its digits is 4200, while the sum is 28.

The square root of 21745153 is about 4663.1698446443. The cubic root of 21745153 is about 279.1177716501.

Adding to 21745153 its reverse (35154712), we get a palindrome (56899865).

The spelling of 21745153 in words is "twenty-one million, seven hundred forty-five thousand, one hundred fifty-three".