20547731 has 2 divisors, whose sum is σ = 20547732. Its totient is φ = 20547730.

The previous prime is 20547727. The next prime is 20547733. The reversal of 20547731 is 13774502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20547731 - 2² = 20547727 is a prime.

It is a super-2 number, since 2×20547731² = 844418498496722, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 20547733, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20547694 and 20547703.

It is not a weakly prime, because it can be changed into another prime (20547733) 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, 10273865 + 10273866.

It is an arithmetic number, because the mean of its divisors is an integer number (10273866).

Almost surely, 2^20547731 is an apocalyptic number.

20547731 is a deficient number, since it is larger than the sum of its proper divisors (1).

20547731 is an equidigital number, since it uses as much as digits as its factorization.

20547731 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5880, while the sum is 29.

The square root of 20547731 is about 4532.9605116303. The cubic root of 20547731 is about 273.8974299516.

The spelling of 20547731 in words is "twenty million, five hundred forty-seven thousand, seven hundred thirty-one".