645104400 has 60 divisors (see below), whose sum is σ = 2066488272. Its totient is φ = 172027520.

The previous prime is 645104381. The next prime is 645104419. The reversal of 645104400 is 4401546.

It is an interprime number because it is at equal distance from previous prime (645104381) and next prime (645104419).

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 267594 + ... + 269993.

Almost surely, 2^645104400 is an apocalyptic number.

645104400 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

645104400 is an abundant number, since it is smaller than the sum of its proper divisors (1421383872).

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

645104400 is a wasteful number, since it uses less digits than its factorization.

645104400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 537608 (or 537597 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 24.

The square root of 645104400 is about 25398.9054882292. The cubic root of 645104400 is about 864.0588737317.

Adding to 645104400 its reverse (4401546), we get a palindrome (649505946).

The spelling of 645104400 in words is "six hundred forty-five million, one hundred four thousand, four hundred".