645397475400 has 384 divisors, whose sum is σ = 2394532454400. Its totient is φ = 159311750400.

The previous prime is 645397475357. The next prime is 645397475419. The reversal of 645397475400 is 4574793546.

645397475400 is a `hidden beast` number, since 6 + 4 + 5 + 3 + 97 + 4 + 7 + 540 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3766387 + ... + 3934013.

It is an arithmetic number, because the mean of its divisors is an integer number (6235761600).

Almost surely, 2^645397475400 is an apocalyptic number.

645397475400 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 645397475400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1197266227200).

645397475400 is an abundant number, since it is smaller than the sum of its proper divisors (1749134979000).

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

645397475400 is a wasteful number, since it uses less digits than its factorization.

645397475400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167706 (or 167691 counting only the distinct ones).

The product of its (nonzero) digits is 12700800, while the sum is 54.

The spelling of 645397475400 in words is "six hundred forty-five billion, three hundred ninety-seven million, four hundred seventy-five thousand, four hundred".