638647461 has 12 divisors (see below), whose sum is σ = 952248960. Its totient is φ = 412030440.

The previous prime is 638647433. The next prime is 638647469. The reversal of 638647461 is 164746836.

It is a happy number.

638647461 is a `hidden beast` number, since 638 + 6 + 4 + 7 + 4 + 6 + 1 = 666.

It is not a de Polignac number, because 638647461 - 2⁶ = 638647397 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638647469) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1144251 + ... + 1144808.

It is an arithmetic number, because the mean of its divisors is an integer number (79354080).

Almost surely, 2^638647461 is an apocalyptic number.

It is an amenable number.

638647461 is a deficient number, since it is larger than the sum of its proper divisors (313601499).

638647461 is a wasteful number, since it uses less digits than its factorization.

638647461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2289096 (or 2289093 counting only the distinct ones).

The product of its digits is 580608, while the sum is 45.

The square root of 638647461 is about 25271.4752438396. The cubic root of 638647461 is about 861.1663734952.

The spelling of 638647461 in words is "six hundred thirty-eight million, six hundred forty-seven thousand, four hundred sixty-one".