21633573 has 8 divisors (see below), whose sum is σ = 31063648. Its totient is φ = 13312944.

The previous prime is 21633569. The next prime is 21633587. The reversal of 21633573 is 37533612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21633573 - 2² = 21633569 is a prime.

It is a super-2 number, since 2×21633573² = 936022961492658, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21633573.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21633553) 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, 277315 + ... + 277392.

It is an arithmetic number, because the mean of its divisors is an integer number (3882956).

Almost surely, 2^21633573 is an apocalyptic number.

It is an amenable number.

21633573 is a deficient number, since it is larger than the sum of its proper divisors (9430075).

21633573 is a wasteful number, since it uses less digits than its factorization.

21633573 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 554723.

The product of its digits is 11340, while the sum is 30.

The square root of 21633573 is about 4651.1904927663. The cubic root of 21633573 is about 278.6395442711.

The spelling of 21633573 in words is "twenty-one million, six hundred thirty-three thousand, five hundred seventy-three".