20997653 has 8 divisors (see below), whose sum is σ = 21772800. Its totient is φ = 20225968.

The previous prime is 20997649. The next prime is 20997659. The reversal of 20997653 is 35679902.

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 20997653 - 2² = 20997649 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20997653.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20997659) 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, 23900 + ... + 24762.

It is an arithmetic number, because the mean of its divisors is an integer number (2721600).

Almost surely, 2^20997653 is an apocalyptic number.

It is an amenable number.

20997653 is a deficient number, since it is larger than the sum of its proper divisors (775147).

20997653 is an equidigital number, since it uses as much as digits as its factorization.

20997653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1731.

The product of its (nonzero) digits is 102060, while the sum is 41.

The square root of 20997653 is about 4582.3196091063. The cubic root of 20997653 is about 275.8821391678.

The spelling of 20997653 in words is "twenty million, nine hundred ninety-seven thousand, six hundred fifty-three".