21023255 has 8 divisors (see below), whose sum is σ = 27521424. Its totient is φ = 15289600.

The previous prime is 21023213. The next prime is 21023257. The reversal of 21023255 is 55232012.

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

It is a de Polignac number, because none of the positive numbers 2^k-21023255 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 (21023257) 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, 191066 + ... + 191175.

It is an arithmetic number, because the mean of its divisors is an integer number (3440178).

Almost surely, 2^21023255 is an apocalyptic number.

21023255 is a deficient number, since it is larger than the sum of its proper divisors (6498169).

21023255 is a wasteful number, since it uses less digits than its factorization.

21023255 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 382257.

The product of its (nonzero) digits is 600, while the sum is 20.

The square root of 21023255 is about 4585.1123214159. The cubic root of 21023255 is about 275.9942194056.

Adding to 21023255 its reverse (55232012), we get a palindrome (76255267).

The spelling of 21023255 in words is "twenty-one million, twenty-three thousand, two hundred fifty-five".