21301553 has 8 divisors (see below), whose sum is σ = 26217408. Its totient is φ = 16853904.

The previous prime is 21301549. The next prime is 21301571. The reversal of 21301553 is 35510312.

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 21301553 - 2² = 21301549 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21301523) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 116951 + ... + 117132.

It is an arithmetic number, because the mean of its divisors is an integer number (3277176).

Almost surely, 2^21301553 is an apocalyptic number.

It is an amenable number.

21301553 is a deficient number, since it is larger than the sum of its proper divisors (4915855).

21301553 is a wasteful number, since it uses less digits than its factorization.

21301553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 234103.

The product of its (nonzero) digits is 450, while the sum is 20.

The square root of 21301553 is about 4615.3605492962. The cubic root of 21301553 is about 277.2067209685.

Adding to 21301553 its reverse (35510312), we get a palindrome (56811865).

The spelling of 21301553 in words is "twenty-one million, three hundred one thousand, five hundred fifty-three".