645271401600 has 960 divisors, whose sum is σ = 2760243868800. Its totient is φ = 145384243200.

The previous prime is 645271401583. The next prime is 645271401617. The reversal of 645271401600 is 6104172546.

645271401600 is a `hidden beast` number, since 6 + 4 + 5 + 2 + 7 + 1 + 40 + 1 + 600 = 666.

It is an interprime number because it is at equal distance from previous prime (645271401583) and next prime (645271401617).

It is a tau number, because it is divible by the number of its divisors (960).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 128819896 + ... + 128824904.

It is an arithmetic number, because the mean of its divisors is an integer number (2875254030).

Almost surely, 2^645271401600 is an apocalyptic number.

645271401600 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 645271401600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1380121934400).

645271401600 is an abundant number, since it is smaller than the sum of its proper divisors (2114972467200).

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

645271401600 is a wasteful number, since it uses less digits than its factorization.

645271401600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5123 (or 5097 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The spelling of 645271401600 in words is "six hundred forty-five billion, two hundred seventy-one million, four hundred one thousand, six hundred".