21642033 has 16 divisors (see below), whose sum is σ = 34116480. Its totient is φ = 11940096.

The previous prime is 21642017. The next prime is 21642067. The reversal of 21642033 is 33024612.

It is a happy number.

It is not a de Polignac number, because 21642033 - 2⁴ = 21642017 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (21642013) 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, 17160 + ... + 18377.

It is an arithmetic number, because the mean of its divisors is an integer number (2132280).

Almost surely, 2^21642033 is an apocalyptic number.

It is an amenable number.

21642033 is a deficient number, since it is larger than the sum of its proper divisors (12474447).

21642033 is a wasteful number, since it uses less digits than its factorization.

21642033 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35576.

The product of its (nonzero) digits is 864, while the sum is 21.

The square root of 21642033 is about 4652.0998484555. The cubic root of 21642033 is about 278.6758610233.

Adding to 21642033 its reverse (33024612), we get a palindrome (54666645).

The spelling of 21642033 in words is "twenty-one million, six hundred forty-two thousand, thirty-three".