21320455 has 8 divisors (see below), whose sum is σ = 27552672. Its totient is φ = 15744288.

The previous prime is 21320447. The next prime is 21320479. The reversal of 21320455 is 55402312.

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 21320455 - 2³ = 21320447 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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, 163939 + ... + 164068.

It is an arithmetic number, because the mean of its divisors is an integer number (3444084).

Almost surely, 2^21320455 is an apocalyptic number.

21320455 is a deficient number, since it is larger than the sum of its proper divisors (6232217).

21320455 is a wasteful number, since it uses less digits than its factorization.

21320455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328025.

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

The square root of 21320455 is about 4617.4078225775. The cubic root of 21320455 is about 277.2886901464.

Adding to 21320455 its reverse (55402312), we get a palindrome (76722767).

It can be divided in two parts, 2132045 and 5, that multiplied together give a square (10660225 = 3265²).

The spelling of 21320455 in words is "twenty-one million, three hundred twenty thousand, four hundred fifty-five".