638336740 has 24 divisors (see below), whose sum is σ = 1419361272. Its totient is φ = 240314880.

The previous prime is 638336737. The next prime is 638336761. The reversal of 638336740 is 47633836.

It can be written as a sum of positive squares in 4 ways, for example, as 29333056 + 609003684 = 5416^2 + 24678^2 .

It is a junction number, because it is equal to n+sod(n) for n = 638336693 and 638336702.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 938391 + ... + 939070.

It is an arithmetic number, because the mean of its divisors is an integer number (59140053).

Almost surely, 2^638336740 is an apocalyptic number.

It is an amenable number.

638336740 is an abundant number, since it is smaller than the sum of its proper divisors (781024532).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

638336740 is a wasteful number, since it uses less digits than its factorization.

638336740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1877487 (or 1877485 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 40.

The square root of 638336740 is about 25265.3268334292. The cubic root of 638336740 is about 861.0266898145.

The spelling of 638336740 in words is "six hundred thirty-eight million, three hundred thirty-six thousand, seven hundred forty".