638473547 has 4 divisors (see below), whose sum is σ = 638528856. Its totient is φ = 638418240.

The previous prime is 638473543. The next prime is 638473559. The reversal of 638473547 is 745374836.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 638473547 - 2² = 638473543 is a prime.

It is a super-2 number, since 2×638473547² = 815296940437522418, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638473543) 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, 3029 + ... + 35862.

It is an arithmetic number, because the mean of its divisors is an integer number (159632214).

Almost surely, 2^638473547 is an apocalyptic number.

638473547 is a deficient number, since it is larger than the sum of its proper divisors (55309).

638473547 is a wasteful number, since it uses less digits than its factorization.

638473547 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55308.

The product of its digits is 1693440, while the sum is 47.

The square root of 638473547 is about 25268.0340944839. The cubic root of 638473547 is about 861.0881965694.

The spelling of 638473547 in words is "six hundred thirty-eight million, four hundred seventy-three thousand, five hundred forty-seven".