21453315 has 16 divisors (see below), whose sum is σ = 36966048. Its totient is φ = 10561536.

The previous prime is 21453307. The next prime is 21453323. The reversal of 21453315 is 51335412.

It is an interprime number because it is at equal distance from previous prime (21453307) and next prime (21453323).

It is not a de Polignac number, because 21453315 - 2³ = 21453307 is a prime.

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 15 ways as a sum of consecutive naturals, for example, 54814 + ... + 55203.

It is an arithmetic number, because the mean of its divisors is an integer number (2310378).

Almost surely, 2^21453315 is an apocalyptic number.

21453315 is a deficient number, since it is larger than the sum of its proper divisors (15512733).

21453315 is a wasteful number, since it uses less digits than its factorization.

21453315 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110038.

The product of its digits is 1800, while the sum is 24.

The square root of 21453315 is about 4631.7723389649. The cubic root of 21453315 is about 277.8634795412.

Adding to 21453315 its reverse (51335412), we get a palindrome (72788727).

It can be divided in two parts, 2145 and 3315, that added together give a triangular number (5460 = T₁₀₄).

The spelling of 21453315 in words is "twenty-one million, four hundred fifty-three thousand, three hundred fifteen".