20997047 has 2 divisors, whose sum is σ = 20997048. Its totient is φ = 20997046.

The previous prime is 20997017. The next prime is 20997059. The reversal of 20997047 is 74079902.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20997047 - 2¹⁰ = 20996023 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20997047.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20997017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10498523 + 10498524.

It is an arithmetic number, because the mean of its divisors is an integer number (10498524).

Almost surely, 2^20997047 is an apocalyptic number.

20997047 is a deficient number, since it is larger than the sum of its proper divisors (1).

20997047 is an equidigital number, since it uses as much as digits as its factorization.

20997047 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31752, while the sum is 38.

The square root of 20997047 is about 4582.2534849133. The cubic root of 20997047 is about 275.8794851222.

The spelling of 20997047 in words is "twenty million, nine hundred ninety-seven thousand, forty-seven".