20749549 has 4 divisors (see below), whose sum is σ = 20982780. Its totient is φ = 20516320.

The previous prime is 20749543. The next prime is 20749601. The reversal of 20749549 is 94594702.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6985449 + 13764100 = 2643^2 + 3710^2 .

It is a cyclic number.

It is not a de Polignac number, because 20749549 - 2⁵ = 20749517 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 (20749543) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 116482 + ... + 116659.

It is an arithmetic number, because the mean of its divisors is an integer number (5245695).

Almost surely, 2^20749549 is an apocalyptic number.

It is an amenable number.

20749549 is a deficient number, since it is larger than the sum of its proper divisors (233231).

20749549 is an equidigital number, since it uses as much as digits as its factorization.

20749549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 233230.

The product of its (nonzero) digits is 90720, while the sum is 40.

The square root of 20749549 is about 4555.1672856219. The cubic root of 20749549 is about 274.7912421189.

The spelling of 20749549 in words is "twenty million, seven hundred forty-nine thousand, five hundred forty-nine".