21105053 has 4 divisors (see below), whose sum is σ = 22022688. Its totient is φ = 20187420.

The previous prime is 21105047. The next prime is 21105107. The reversal of 21105053 is 35050112.

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 21105053 - 2⁶ = 21104989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21105013) 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, 458783 + ... + 458828.

It is an arithmetic number, because the mean of its divisors is an integer number (5505672).

Almost surely, 2^21105053 is an apocalyptic number.

21105053 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21105053 is a deficient number, since it is larger than the sum of its proper divisors (917635).

21105053 is an equidigital number, since it uses as much as digits as its factorization.

21105053 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 917634.

The product of its (nonzero) digits is 150, while the sum is 17.

The square root of 21105053 is about 4594.0236177016. The cubic root of 21105053 is about 276.3517054174.

Adding to 21105053 its reverse (35050112), we get a palindrome (56155165).

The spelling of 21105053 in words is "twenty-one million, one hundred five thousand, fifty-three".