639770624 has 56 divisors (see below), whose sum is σ = 1324074060. Its totient is φ = 308740096.

The previous prime is 639770611. The next prime is 639770629. The reversal of 639770624 is 426077936.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 639078400 + 692224 = 25280^2 + 832^2 .

It is not an unprimeable number, because it can be changed into a prime (639770629) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 236222 + ... + 238914.

Almost surely, 2^639770624 is an apocalyptic number.

639770624 is a gapful number since it is divisible by the number (64) 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 639770624, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (662037030).

639770624 is an abundant number, since it is smaller than the sum of its proper divisors (684303436).

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

639770624 is an equidigital number, since it uses as much as digits as its factorization.

639770624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2748 (or 2724 counting only the distinct ones).

The product of its (nonzero) digits is 381024, while the sum is 44.

The square root of 639770624 is about 25293.6874338243. The cubic root of 639770624 is about 861.6709104584.

The spelling of 639770624 in words is "six hundred thirty-nine million, seven hundred seventy thousand, six hundred twenty-four".