638620530 has 64 divisors (see below), whose sum is σ = 1603584000. Its totient is φ = 162461376.

The previous prime is 638620519. The next prime is 638620531. The reversal of 638620530 is 35026836.

It is a junction number, because it is equal to n+sod(n) for n = 638620491 and 638620500.

It is not an unprimeable number, because it can be changed into a prime (638620531) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 318471 + ... + 320469.

It is an arithmetic number, because the mean of its divisors is an integer number (25056000).

Almost surely, 2^638620530 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638620530, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (801792000).

638620530 is an abundant number, since it is smaller than the sum of its proper divisors (964963470).

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

638620530 is a wasteful number, since it uses less digits than its factorization.

638620530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2495.

The product of its (nonzero) digits is 25920, while the sum is 33.

The square root of 638620530 is about 25270.9424042714. The cubic root of 638620530 is about 861.1542685396.

The spelling of 638620530 in words is "six hundred thirty-eight million, six hundred twenty thousand, five hundred thirty".