20992747 has 2 divisors, whose sum is σ = 20992748. Its totient is φ = 20992746.

The previous prime is 20992711. The next prime is 20992757. The reversal of 20992747 is 74729902.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20992747 is a prime.

It is not a weakly prime, because it can be changed into another prime (20992757) 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, 10496373 + 10496374.

It is an arithmetic number, because the mean of its divisors is an integer number (10496374).

Almost surely, 2^20992747 is an apocalyptic number.

20992747 is a deficient number, since it is larger than the sum of its proper divisors (1).

20992747 is an equidigital number, since it uses as much as digits as its factorization.

20992747 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 63504, while the sum is 40.

The square root of 20992747 is about 4581.7842594343. The cubic root of 20992747 is about 275.8606513187.

The spelling of 20992747 in words is "twenty million, nine hundred ninety-two thousand, seven hundred forty-seven".