638066755648 has 56 divisors (see below), whose sum is σ = 1447745745600. Its totient is φ = 273324615168.

The previous prime is 638066755633. The next prime is 638066755663. The reversal of 638066755648 is 846557660836.

It is an interprime number because it is at equal distance from previous prime (638066755633) and next prime (638066755663).

It is a tau number, because it is divible by the number of its divisors (56).

It is a Harshad number since it is a multiple of its sum of digits (64).

It is a self number, because there is not a number n which added to its sum of digits gives 638066755648.

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, 582723 + ... + 1271101.

It is an arithmetic number, because the mean of its divisors is an integer number (25852602600).

Almost surely, 2^638066755648 is an apocalyptic number.

It is an amenable number.

638066755648 is an abundant number, since it is smaller than the sum of its proper divisors (809678989952).

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

638066755648 is a wasteful number, since it uses less digits than its factorization.

638066755648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 690467 (or 690457 counting only the distinct ones).

The product of its (nonzero) digits is 174182400, while the sum is 64.

The spelling of 638066755648 in words is "six hundred thirty-eight billion, sixty-six million, seven hundred fifty-five thousand, six hundred forty-eight".