20478547 has 2 divisors, whose sum is σ = 20478548. Its totient is φ = 20478546.

The previous prime is 20478541. The next prime is 20478551. The reversal of 20478547 is 74587402.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20478547 - 2³ = 20478539 is a prime.

It is not a weakly prime, because it can be changed into another prime (20478541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10239273 + 10239274.

It is an arithmetic number, because the mean of its divisors is an integer number (10239274).

Almost surely, 2^20478547 is an apocalyptic number.

20478547 is a deficient number, since it is larger than the sum of its proper divisors (1).

20478547 is an equidigital number, since it uses as much as digits as its factorization.

20478547 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 62720, while the sum is 37.

The square root of 20478547 is about 4525.3228614100. The cubic root of 20478547 is about 273.5896810156.

It can be divided in two parts, 20478 and 547, that added together give a square (21025 = 145²).

The spelling of 20478547 in words is "twenty million, four hundred seventy-eight thousand, five hundred forty-seven".