20577971 has 4 divisors (see below), whose sum is σ = 20587344. Its totient is φ = 20568600.

The previous prime is 20577959. The next prime is 20577979. The reversal of 20577971 is 17977502.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 17977502 = 2 ⋅8988751.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20577971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20577979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 581 + ... + 6441.

It is an arithmetic number, because the mean of its divisors is an integer number (5146836).

Almost surely, 2^20577971 is an apocalyptic number.

20577971 is a deficient number, since it is larger than the sum of its proper divisors (9373).

20577971 is an equidigital number, since it uses as much as digits as its factorization.

20577971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9372.

The product of its (nonzero) digits is 30870, while the sum is 38.

The square root of 20577971 is about 4536.2948537325. The cubic root of 20577971 is about 274.0317286148.

The spelling of 20577971 in words is "twenty million, five hundred seventy-seven thousand, nine hundred seventy-one".