20947547 has 2 divisors, whose sum is σ = 20947548. Its totient is φ = 20947546.

The previous prime is 20947529. The next prime is 20947559. The reversal of 20947547 is 74574902.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20947547 - 2¹⁸ = 20685403 is a prime.

It is a super-3 number, since 3×20947547³ (a number of 23 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20947547.

It is not a weakly prime, because it can be changed into another prime (20947517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10473773 + 10473774.

It is an arithmetic number, because the mean of its divisors is an integer number (10473774).

Almost surely, 2^20947547 is an apocalyptic number.

20947547 is a deficient number, since it is larger than the sum of its proper divisors (1).

20947547 is an equidigital number, since it uses as much as digits as its factorization.

20947547 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 70560, while the sum is 38.

The square root of 20947547 is about 4576.8490252574. The cubic root of 20947547 is about 275.6625215997.

The spelling of 20947547 in words is "twenty million, nine hundred forty-seven thousand, five hundred forty-seven".