20746478947 has 4 divisors (see below), whose sum is σ = 21137922000. Its totient is φ = 20355035896.

The previous prime is 20746478941. The next prime is 20746478953. The reversal of 20746478947 is 74987464702.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (20746478941) and next prime (20746478953).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20746478947 is a prime.

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20746478891 and 20746478900.

It is not an unprimeable number, because it can be changed into a prime (20746478941) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 195721447 + ... + 195721552.

It is an arithmetic number, because the mean of its divisors is an integer number (5284480500).

Almost surely, 2^20746478947 is an apocalyptic number.

20746478947 is a deficient number, since it is larger than the sum of its proper divisors (391443053).

20746478947 is an equidigital number, since it uses as much as digits as its factorization.

20746478947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 391443052.

The product of its (nonzero) digits is 18966528, while the sum is 58.

The spelling of 20746478947 in words is "twenty billion, seven hundred forty-six million, four hundred seventy-eight thousand, nine hundred forty-seven".