634544640 has 120 divisors (see below), whose sum is σ = 2197686348. Its totient is φ = 169205760.

The previous prime is 634544639. The next prime is 634544663. The reversal of 634544640 is 46445436.

634544640 is a `hidden beast` number, since 6 + 3 + 4 + 5 + 4 + 4 + 640 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 625400064 + 9144576 = 25008^2 + 3024^2 .

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 634544595 and 634544604.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9270 + ... + 36810.

Almost surely, 2^634544640 is an apocalyptic number.

634544640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 634544640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1098843174).

634544640 is an abundant number, since it is smaller than the sum of its proper divisors (1563141708).

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

634544640 is a wasteful number, since it uses less digits than its factorization.

634544640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27570 (or 27551 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 36.

The square root of 634544640 is about 25190.1695111407. The cubic root of 634544640 is about 859.3182987868.

The spelling of 634544640 in words is "six hundred thirty-four million, five hundred forty-four thousand, six hundred forty".