20997550 has 48 divisors (see below), whose sum is σ = 47273760. Its totient is φ = 6773760.

The previous prime is 20997541. The next prime is 20997553. The reversal of 20997550 is 5579902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20997553) 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 23 ways as a sum of consecutive naturals, for example, 4186 + ... + 7714.

It is an arithmetic number, because the mean of its divisors is an integer number (984870).

Almost surely, 2^20997550 is an apocalyptic number.

20997550 is an abundant number, since it is smaller than the sum of its proper divisors (26276210).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20997550 is a wasteful number, since it uses less digits than its factorization.

20997550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3565 (or 3560 counting only the distinct ones).

The product of its (nonzero) digits is 28350, while the sum is 37.

The square root of 20997550 is about 4582.3083702431. The cubic root of 20997550 is about 275.8816880713.

The spelling of 20997550 in words is "twenty million, nine hundred ninety-seven thousand, five hundred fifty".