20447478477 has 6 divisors (see below), whose sum is σ = 29535246702. Its totient is φ = 13631652312.

The previous prime is 20447478419. The next prime is 20447478487. The reversal of 20447478477 is 77487474402.

20447478477 is a `hidden beast` number, since 20 + 4 + 474 + 7 + 84 + 77 = 666.

It can be written as a sum of positive squares in only one way, i.e., 16426523556 + 4020954921 = 128166^2 + 63411^2 .

It is not a de Polignac number, because 20447478477 - 2⁶ = 20447478413 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20447478487) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1135971018 + ... + 1135971035.

It is an arithmetic number, because the mean of its divisors is an integer number (4922541117).

Almost surely, 2^20447478477 is an apocalyptic number.

It is an amenable number.

20447478477 is a deficient number, since it is larger than the sum of its proper divisors (9087768225).

20447478477 is a wasteful number, since it uses less digits than its factorization.

20447478477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2271942059 (or 2271942056 counting only the distinct ones).

The product of its (nonzero) digits is 9834496, while the sum is 54.

The spelling of 20447478477 in words is "twenty billion, four hundred forty-seven million, four hundred seventy-eight thousand, four hundred seventy-seven".