645772800 has 240 divisors, whose sum is σ = 2173735872. Its totient is φ = 168960000.

The previous prime is 645772793. The next prime is 645772807. The reversal of 645772800 is 8277546.

It is an interprime number because it is at equal distance from previous prime (645772793) and next prime (645772807).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645772807) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2572675 + ... + 2572925.

Almost surely, 2^645772800 is an apocalyptic number.

645772800 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 645772800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1086867936).

645772800 is an abundant number, since it is smaller than the sum of its proper divisors (1527963072).

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

645772800 is a wasteful number, since it uses less digits than its factorization.

645772800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 349 (or 328 counting only the distinct ones).

The product of its (nonzero) digits is 94080, while the sum is 39.

The square root of 645772800 is about 25412.0601290017. The cubic root of 645772800 is about 864.3571911315.

The spelling of 645772800 in words is "six hundred forty-five million, seven hundred seventy-two thousand, eight hundred".