645308400 has 480 divisors, whose sum is σ = 2479841280. Its totient is φ = 141696000.

The previous prime is 645308399. The next prime is 645308407. The reversal of 645308400 is 4803546.

It is a super-2 number, since 2×645308400² = 832845862221120000, which contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645308407) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 7774759 + ... + 7774841.

It is an arithmetic number, because the mean of its divisors is an integer number (5166336).

Almost surely, 2^645308400 is an apocalyptic number.

645308400 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 645308400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1239920640).

645308400 is an abundant number, since it is smaller than the sum of its proper divisors (1834532880).

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

645308400 is a wasteful number, since it uses less digits than its factorization.

645308400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165 (or 154 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 30.

The square root of 645308400 is about 25402.9210918745. The cubic root of 645308400 is about 864.1499439694.

The spelling of 645308400 in words is "six hundred forty-five million, three hundred eight thousand, four hundred".