21082553 has 4 divisors (see below), whose sum is σ = 21091968. Its totient is φ = 21073140.

The previous prime is 21082543. The next prime is 21082577. The reversal of 21082553 is 35528012.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21082553 - 2¹² = 21078457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21082543) 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, 800 + ... + 6542.

It is an arithmetic number, because the mean of its divisors is an integer number (5272992).

Almost surely, 2^21082553 is an apocalyptic number.

It is an amenable number.

21082553 is a deficient number, since it is larger than the sum of its proper divisors (9415).

21082553 is an equidigital number, since it uses as much as digits as its factorization.

21082553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9414.

The product of its (nonzero) digits is 2400, while the sum is 26.

The square root of 21082553 is about 4591.5741309490. The cubic root of 21082553 is about 276.2534647368.

The spelling of 21082553 in words is "twenty-one million, eighty-two thousand, five hundred fifty-three".