21354621 has 4 divisors (see below), whose sum is σ = 28472832. Its totient is φ = 14236412.

The previous prime is 21354589. The next prime is 21354653. The reversal of 21354621 is 12645312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (21354589) and next prime (21354653).

It is a cyclic number.

It is not a de Polignac number, because 21354621 - 2⁵ = 21354589 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21354591 and 21354600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21354721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3559101 + ... + 3559106.

It is an arithmetic number, because the mean of its divisors is an integer number (7118208).

Almost surely, 2^21354621 is an apocalyptic number.

It is an amenable number.

21354621 is a deficient number, since it is larger than the sum of its proper divisors (7118211).

21354621 is an equidigital number, since it uses as much as digits as its factorization.

21354621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7118210.

The product of its digits is 1440, while the sum is 24.

The square root of 21354621 is about 4621.1060364376. The cubic root of 21354621 is about 277.4367293460.

Adding to 21354621 its reverse (12645312), we get a palindrome (33999933).

The spelling of 21354621 in words is "twenty-one million, three hundred fifty-four thousand, six hundred twenty-one".