21321653 has 8 divisors (see below), whose sum is σ = 21577920. Its totient is φ = 21067200.

The previous prime is 21321647. The next prime is 21321661. The reversal of 21321653 is 35612312.

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

It is a cyclic number.

It is not a de Polignac number, because 21321653 - 2⁶ = 21321589 is a prime.

It is a super-2 number, since 2×21321653² = 909225773304818, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321623) 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, 50678 + ... + 51096.

It is an arithmetic number, because the mean of its divisors is an integer number (2697240).

Almost surely, 2^21321653 is an apocalyptic number.

It is an amenable number.

21321653 is a deficient number, since it is larger than the sum of its proper divisors (256267).

21321653 is a wasteful number, since it uses less digits than its factorization.

21321653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 907.

The product of its digits is 1080, while the sum is 23.

The square root of 21321653 is about 4617.5375472215. The cubic root of 21321653 is about 277.2938836821.

Adding to 21321653 its reverse (35612312), we get a palindrome (56933965).

The spelling of 21321653 in words is "twenty-one million, three hundred twenty-one thousand, six hundred fifty-three".