21451355 has 8 divisors (see below), whose sum is σ = 25970112. Its totient is φ = 17008768.

The previous prime is 21451351. The next prime is 21451357. The reversal of 21451355 is 55315412.

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 21451355 - 2² = 21451351 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21451351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18419 + ... + 19548.

It is an arithmetic number, because the mean of its divisors is an integer number (3246264).

Almost surely, 2^21451355 is an apocalyptic number.

21451355 is a deficient number, since it is larger than the sum of its proper divisors (4518757).

21451355 is a wasteful number, since it uses less digits than its factorization.

21451355 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38085.

The product of its digits is 3000, while the sum is 26.

The square root of 21451355 is about 4631.5607520576. The cubic root of 21451355 is about 277.8550173058.

Adding to 21451355 its reverse (55315412), we get a palindrome (76766767).

The spelling of 21451355 in words is "twenty-one million, four hundred fifty-one thousand, three hundred fifty-five".