20992157 has 2 divisors, whose sum is σ = 20992158. Its totient is φ = 20992156.

The previous prime is 20992151. The next prime is 20992159. The reversal of 20992157 is 75129902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20666116 + 326041 = 4546^2 + 571^2 .

It is a cyclic number.

It is not a de Polignac number, because 20992157 - 2¹² = 20988061 is a prime.

Together with 20992159, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20992151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10496078 + 10496079.

It is an arithmetic number, because the mean of its divisors is an integer number (10496079).

Almost surely, 2^20992157 is an apocalyptic number.

It is an amenable number.

20992157 is a deficient number, since it is larger than the sum of its proper divisors (1).

20992157 is an equidigital number, since it uses as much as digits as its factorization.

20992157 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11340, while the sum is 35.

The square root of 20992157 is about 4581.7198735846. The cubic root of 20992157 is about 275.8580669450.

The spelling of 20992157 in words is "twenty million, nine hundred ninety-two thousand, one hundred fifty-seven".