20709151 has 4 divisors (see below), whose sum is σ = 20992912. Its totient is φ = 20425392.

The previous prime is 20709133. The next prime is 20709203. The reversal of 20709151 is 15190702.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15190702 = 2 ⋅7595351.

It is a cyclic number.

It is not a de Polignac number, because 20709151 - 2¹⁹ = 20184863 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 (20709121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 141771 + ... + 141916.

It is an arithmetic number, because the mean of its divisors is an integer number (5248228).

Almost surely, 2^20709151 is an apocalyptic number.

20709151 is a deficient number, since it is larger than the sum of its proper divisors (283761).

20709151 is an equidigital number, since it uses as much as digits as its factorization.

20709151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 283760.

The product of its (nonzero) digits is 630, while the sum is 25.

The square root of 20709151 is about 4550.7308204287. The cubic root of 20709151 is about 274.6127927991.

Adding to 20709151 its reverse (15190702), we get a palindrome (35899853).

The spelling of 20709151 in words is "twenty million, seven hundred nine thousand, one hundred fifty-one".