20992757 has 2 divisors, whose sum is σ = 20992758. Its totient is φ = 20992756.

The previous prime is 20992747. The next prime is 20992771. The reversal of 20992757 is 75729902.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17926756 + 3066001 = 4234^2 + 1751^2 .

It is a cyclic number.

It is not a de Polignac number, because 20992757 - 2⁶ = 20992693 is a prime.

It is a super-2 number, since 2×20992757² = 881391692922098, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20992747) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10496378 + 10496379.

It is an arithmetic number, because the mean of its divisors is an integer number (10496379).

Almost surely, 2^20992757 is an apocalyptic number.

It is an amenable number.

20992757 is a deficient number, since it is larger than the sum of its proper divisors (1).

20992757 is an equidigital number, since it uses as much as digits as its factorization.

20992757 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 79380, while the sum is 41.

The square root of 20992757 is about 4581.7853507121. The cubic root of 20992757 is about 275.8606951212.

The spelling of 20992757 in words is "twenty million, nine hundred ninety-two thousand, seven hundred fifty-seven".