20578361 has 4 divisors (see below), whose sum is σ = 20619300. Its totient is φ = 20537424.

The previous prime is 20578357. The next prime is 20578367. The reversal of 20578361 is 16387502.

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: 16387502 = 2 ⋅8193751.

It can be written as a sum of positive squares in 2 ways, for example, as 17480761 + 3097600 = 4181^2 + 1760^2 .

It is a cyclic number.

It is not a de Polignac number, because 20578361 - 2² = 20578357 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20578367) 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, 19706 + ... + 20723.

It is an arithmetic number, because the mean of its divisors is an integer number (5154825).

Almost surely, 2^20578361 is an apocalyptic number.

It is an amenable number.

20578361 is a deficient number, since it is larger than the sum of its proper divisors (40939).

20578361 is an equidigital number, since it uses as much as digits as its factorization.

20578361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40938.

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 20578361 is about 4536.3378401526. The cubic root of 20578361 is about 274.0334597816.

The spelling of 20578361 in words is "twenty million, five hundred seventy-eight thousand, three hundred sixty-one".