646289280 has 640 divisors, whose sum is σ = 2861369280. Its totient is φ = 135364608.

The previous prime is 646289263. The next prime is 646289291. The reversal of 646289280 is 82982646.

It is a tau number, because it is divible by the number of its divisors (640).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 4717372 + ... + 4717508.

Almost surely, 2^646289280 is an apocalyptic number.

646289280 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 646289280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1430684640).

646289280 is an abundant number, since it is smaller than the sum of its proper divisors (2215080000).

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

646289280 is a wasteful number, since it uses less digits than its factorization.

646289280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188 (or 167 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 45.

The square root of 646289280 is about 25422.2202020201. The cubic root of 646289280 is about 864.5875632999.

The spelling of 646289280 in words is "six hundred forty-six million, two hundred eighty-nine thousand, two hundred eighty".