21229255 has 4 divisors (see below), whose sum is σ = 25475112. Its totient is φ = 16983400.

The previous prime is 21229249. The next prime is 21229261. The reversal of 21229255 is 55292212.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21229249) and next prime (21229261).

It is not a de Polignac number, because 21229255 - 2¹³ = 21221063 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2122921 + ... + 2122930.

It is an arithmetic number, because the mean of its divisors is an integer number (6368778).

Almost surely, 2^21229255 is an apocalyptic number.

21229255 is a deficient number, since it is larger than the sum of its proper divisors (4245857).

21229255 is an equidigital number, since it uses as much as digits as its factorization.

21229255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4245856.

The product of its digits is 3600, while the sum is 28.

The square root of 21229255 is about 4607.5215680450. The cubic root of 21229255 is about 276.8927499928.

The spelling of 21229255 in words is "twenty-one million, two hundred twenty-nine thousand, two hundred fifty-five".