20549765 has 4 divisors (see below), whose sum is σ = 24659724. Its totient is φ = 16439808.

The previous prime is 20549761. The next prime is 20549783. The reversal of 20549765 is 56794502.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56794502 = 2 ⋅28397251.

It can be written as a sum of positive squares in 2 ways, for example, as 15319396 + 5230369 = 3914^2 + 2287^2 .

It is a cyclic number.

It is not a de Polignac number, because 20549765 - 2² = 20549761 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 (20549761) 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, 2054972 + ... + 2054981.

It is an arithmetic number, because the mean of its divisors is an integer number (6164931).

Almost surely, 2^20549765 is an apocalyptic number.

It is an amenable number.

20549765 is a deficient number, since it is larger than the sum of its proper divisors (4109959).

20549765 is an equidigital number, since it uses as much as digits as its factorization.

20549765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4109958.

The product of its (nonzero) digits is 75600, while the sum is 38.

The square root of 20549765 is about 4533.1848627648. The cubic root of 20549765 is about 273.9064672672.

The spelling of 20549765 in words is "twenty million, five hundred forty-nine thousand, seven hundred sixty-five".