640981200 has 240 divisors, whose sum is σ = 2156022720. Its totient is φ = 162570240.

The previous prime is 640981183. The next prime is 640981219. The reversal of 640981200 is 2189046.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3932319 + ... + 3932481.

It is an arithmetic number, because the mean of its divisors is an integer number (8983428).

Almost surely, 2^640981200 is an apocalyptic number.

640981200 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 640981200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1078011360).

640981200 is an abundant number, since it is smaller than the sum of its proper divisors (1515041520).

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

640981200 is a wasteful number, since it uses less digits than its factorization.

640981200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 326 (or 315 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 640981200 is about 25317.6065219444. The cubic root of 640981200 is about 862.2140534982.

The spelling of 640981200 in words is "six hundred forty million, nine hundred eighty-one thousand, two hundred".