21270653 has 4 divisors (see below), whose sum is σ = 22195488. Its totient is φ = 20345820.

The previous prime is 21270643. The next prime is 21270673. The reversal of 21270653 is 35607212.

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 21270653 - 2⁶ = 21270589 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 (21270643) 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 3 ways as a sum of consecutive naturals, for example, 462383 + ... + 462428.

It is an arithmetic number, because the mean of its divisors is an integer number (5548872).

Almost surely, 2^21270653 is an apocalyptic number.

21270653 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21270653 is a deficient number, since it is larger than the sum of its proper divisors (924835).

21270653 is an equidigital number, since it uses as much as digits as its factorization.

21270653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 924834.

The product of its (nonzero) digits is 2520, while the sum is 26.

The square root of 21270653 is about 4612.0118169840. The cubic root of 21270653 is about 277.0726175566.

Adding to 21270653 its reverse (35607212), we get a palindrome (56877865).

The spelling of 21270653 in words is "twenty-one million, two hundred seventy thousand, six hundred fifty-three".