645408000 has 432 divisors, whose sum is σ = 2437396416. Its totient is φ = 170035200.

The previous prime is 645407993. The next prime is 645408041. The reversal of 645408000 is 804546.

It is a tau number, because it is divible by the number of its divisors (432).

It is a Harshad number since it is a multiple of its sum of digits (27).

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, 7775959 + ... + 7776041.

Almost surely, 2^645408000 is an apocalyptic number.

645408000 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 645408000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1218698208).

645408000 is an abundant number, since it is smaller than the sum of its proper divisors (1791988416).

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

645408000 is an frugal number, since it uses more digits than its factorization.

645408000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129 (or 93 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 645408000 is about 25404.8814207034. The cubic root of 645408000 is about 864.1944007008.

The spelling of 645408000 in words is "six hundred forty-five million, four hundred eight thousand".