21453633 has 8 divisors (see below), whose sum is σ = 31783200. Its totient is φ = 14302404.

The previous prime is 21453623. The next prime is 21453637. The reversal of 21453633 is 33635412.

It is a happy number.

21453633 is a `hidden beast` number, since 21 + 4 + 5 + 3 + 633 = 666.

It is not a de Polignac number, because 21453633 - 2⁶ = 21453569 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 794579 = 21453633 / (2 + 1 + 4 + 5 + 3 + 6 + 3 + 3).

It is a junction number, because it is equal to n+sod(n) for n = 21453597 and 21453606.

It is not an unprimeable number, because it can be changed into a prime (21453637) 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, 397263 + ... + 397316.

It is an arithmetic number, because the mean of its divisors is an integer number (3972900).

Almost surely, 2^21453633 is an apocalyptic number.

It is an amenable number.

21453633 is a deficient number, since it is larger than the sum of its proper divisors (10329567).

21453633 is an equidigital number, since it uses as much as digits as its factorization.

21453633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 794588 (or 794582 counting only the distinct ones).

The product of its digits is 6480, while the sum is 27.

The square root of 21453633 is about 4631.8066669497. The cubic root of 21453633 is about 277.8648524471.

It can be divided in two parts, 2145 and 3633, that added together give a triangular number (5778 = T₁₀₇).

The spelling of 21453633 in words is "twenty-one million, four hundred fifty-three thousand, six hundred thirty-three".