20931151 has 2 divisors, whose sum is σ = 20931152. Its totient is φ = 20931150.

The previous prime is 20931149. The next prime is 20931187. The reversal of 20931151 is 15113902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20931151 - 2¹ = 20931149 is a prime.

It is a super-2 number, since 2×20931151² = 876226164369602, which contains 22 as substring.

Together with 20931149, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20931101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10465575 + 10465576.

It is an arithmetic number, because the mean of its divisors is an integer number (10465576).

Almost surely, 2^20931151 is an apocalyptic number.

20931151 is a deficient number, since it is larger than the sum of its proper divisors (1).

20931151 is an equidigital number, since it uses as much as digits as its factorization.

20931151 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 270, while the sum is 22.

The square root of 20931151 is about 4575.0574859776. The cubic root of 20931151 is about 275.5905809177.

The spelling of 20931151 in words is "twenty million, nine hundred thirty-one thousand, one hundred fifty-one".