21354553 has 4 divisors (see below), whose sum is σ = 23295888. Its totient is φ = 19413220.

The previous prime is 21354551. The next prime is 21354577. The reversal of 21354553 is 35545312.

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 a cyclic number.

It is not a de Polignac number, because 21354553 - 2¹ = 21354551 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21354551) 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, 970651 + ... + 970672.

It is an arithmetic number, because the mean of its divisors is an integer number (5823972).

Almost surely, 2^21354553 is an apocalyptic number.

It is an amenable number.

21354553 is a deficient number, since it is larger than the sum of its proper divisors (1941335).

21354553 is a wasteful number, since it uses less digits than its factorization.

21354553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1941334.

The product of its digits is 9000, while the sum is 28.

The square root of 21354553 is about 4621.0986788858. The cubic root of 21354553 is about 277.4364348631.

Adding to 21354553 its reverse (35545312), we get a palindrome (56899865).

The spelling of 21354553 in words is "twenty-one million, three hundred fifty-four thousand, five hundred fifty-three".