21090053 has 8 divisors (see below), whose sum is σ = 21551040. Its totient is φ = 20633760.

The previous prime is 21090007. The next prime is 21090061. The reversal of 21090053 is 35009012.

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 21090053 - 2²⁰ = 20041477 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21090073) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8801 + ... + 10937.

It is an arithmetic number, because the mean of its divisors is an integer number (2693880).

Almost surely, 2^21090053 is an apocalyptic number.

It is an amenable number.

21090053 is a deficient number, since it is larger than the sum of its proper divisors (460987).

21090053 is a wasteful number, since it uses less digits than its factorization.

21090053 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2347.

The product of its (nonzero) digits is 270, while the sum is 20.

The square root of 21090053 is about 4592.3907717005. The cubic root of 21090053 is about 276.2862193933.

Adding to 21090053 its reverse (35009012), we get a palindrome (56099065).

The spelling of 21090053 in words is "twenty-one million, ninety thousand, fifty-three".