21433645 has 16 divisors (see below), whose sum is σ = 26449920. Its totient is φ = 16665984.

The previous prime is 21433613. The next prime is 21433649. The reversal of 21433645 is 54633412.

It is a cyclic number.

It is not a de Polignac number, because 21433645 - 2⁵ = 21433613 is a prime.

It is a super-3 number, since 3×21433645³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21433649) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 52201 + ... + 52609.

It is an arithmetic number, because the mean of its divisors is an integer number (1653120).

Almost surely, 2^21433645 is an apocalyptic number.

It is an amenable number.

21433645 is a deficient number, since it is larger than the sum of its proper divisors (5016275).

21433645 is a wasteful number, since it uses less digits than its factorization.

21433645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 684.

The product of its digits is 8640, while the sum is 28.

The square root of 21433645 is about 4629.6484747765. The cubic root of 21433645 is about 277.7785315831.

The spelling of 21433645 in words is "twenty-one million, four hundred thirty-three thousand, six hundred forty-five".