20997759 has 8 divisors (see below), whose sum is σ = 28753840. Its totient is φ = 13620096.

The previous prime is 20997731. The next prime is 20997761. The reversal of 20997759 is 95779902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20997759 - 2¹² = 20993663 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 (20997709) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 94474 + ... + 94695.

It is an arithmetic number, because the mean of its divisors is an integer number (3594230).

Almost surely, 2^20997759 is an apocalyptic number.

20997759 is a deficient number, since it is larger than the sum of its proper divisors (7756081).

20997759 is a wasteful number, since it uses less digits than its factorization.

20997759 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189209.

The product of its (nonzero) digits is 357210, while the sum is 48.

The square root of 20997759 is about 4582.3311752862. The cubic root of 20997759 is about 275.8826034016.

The spelling of 20997759 in words is "twenty million, nine hundred ninety-seven thousand, seven hundred fifty-nine".