21344155 has 12 divisors (see below), whose sum is σ = 29795040. Its totient is φ = 14635824.

The previous prime is 21344131. The next prime is 21344159. The reversal of 21344155 is 55144312.

It is a happy number.

It is not a de Polignac number, because 21344155 - 2⁹ = 21343643 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21344159) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 43315 + ... + 43804.

It is an arithmetic number, because the mean of its divisors is an integer number (2482920).

Almost surely, 2^21344155 is an apocalyptic number.

21344155 is a deficient number, since it is larger than the sum of its proper divisors (8450885).

21344155 is an equidigital number, since it uses as much as digits as its factorization.

21344155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87138 (or 87131 counting only the distinct ones).

The product of its digits is 2400, while the sum is 25.

The square root of 21344155 is about 4619.9734847724. The cubic root of 21344155 is about 277.3913975916.

Adding to 21344155 its reverse (55144312), we get a palindrome (76488467).

The spelling of 21344155 in words is "twenty-one million, three hundred forty-four thousand, one hundred fifty-five".