21267553 has 8 divisors (see below), whose sum is σ = 21936960. Its totient is φ = 20608560.

The previous prime is 21267523. The next prime is 21267577. The reversal of 21267553 is 35576212.

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 21267553 - 2⁹ = 21267041 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21267503) 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, 1651 + ... + 6727.

It is an arithmetic number, because the mean of its divisors is an integer number (2742120).

Almost surely, 2^21267553 is an apocalyptic number.

It is an amenable number.

21267553 is a deficient number, since it is larger than the sum of its proper divisors (669407).

21267553 is an equidigital number, since it uses as much as digits as its factorization.

21267553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5207.

The product of its digits is 12600, while the sum is 31.

The square root of 21267553 is about 4611.6757258073. The cubic root of 21267553 is about 277.0591566496.

The spelling of 21267553 in words is "twenty-one million, two hundred sixty-seven thousand, five hundred fifty-three".