645602400 has 360 divisors, whose sum is σ = 2421735624. Its totient is φ = 167961600.

The previous prime is 645602393. The next prime is 645602401. The reversal of 645602400 is 4206546.

It is a happy number.

645602400 is a `hidden beast` number, since 64 + 560 + 2 + 40 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (360).

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

It is a zygodrome in base 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645602401) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 15746380 + ... + 15746420.

Almost surely, 2^645602400 is an apocalyptic number.

645602400 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 645602400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1210867812).

645602400 is an abundant number, since it is smaller than the sum of its proper divisors (1776133224).

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

645602400 is an frugal number, since it uses more digits than its factorization.

645602400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88 (or 51 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 645602400 is about 25408.7071690002. The cubic root of 645602400 is about 864.2811584969.

Adding to 645602400 its reverse (4206546), we get a palindrome (649808946).

The spelling of 645602400 in words is "six hundred forty-five million, six hundred two thousand, four hundred".