21023455 has 8 divisors (see below), whose sum is σ = 25583904. Its totient is φ = 16581600.

The previous prime is 21023419. The next prime is 21023459. The reversal of 21023455 is 55432012.

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

It is not a de Polignac number, because 21023455 - 2¹³ = 21015263 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21023459) 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, 29256 + ... + 29965.

It is an arithmetic number, because the mean of its divisors is an integer number (3197988).

Almost surely, 2^21023455 is an apocalyptic number.

21023455 is a deficient number, since it is larger than the sum of its proper divisors (4560449).

21023455 is an equidigital number, since it uses as much as digits as its factorization.

21023455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59297.

The product of its (nonzero) digits is 1200, while the sum is 22.

The square root of 21023455 is about 4585.1341310806. The cubic root of 21023455 is about 275.9950946058.

Adding to 21023455 its reverse (55432012), we get a palindrome (76455467).

The spelling of 21023455 in words is "twenty-one million, twenty-three thousand, four hundred fifty-five".