645261600 has 288 divisors, whose sum is σ = 2219857920. Its totient is φ = 162570240.

The previous prime is 645261587. The next prime is 645261613. The reversal of 645261600 is 6162546.

It is an interprime number because it is at equal distance from previous prime (645261587) and next prime (645261613).

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

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, 5080737 + ... + 5080863.

It is an arithmetic number, because the mean of its divisors is an integer number (7707840).

Almost surely, 2^645261600 is an apocalyptic number.

645261600 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 645261600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1109928960).

645261600 is an abundant number, since it is smaller than the sum of its proper divisors (1574596320).

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

645261600 is a wasteful number, since it uses less digits than its factorization.

645261600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 252 (or 239 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 645261600 is about 25401.9999212660. Note that the first 4 decimals coincide. The cubic root of 645261600 is about 864.1290530822.

The spelling of 645261600 in words is "six hundred forty-five million, two hundred sixty-one thousand, six hundred".