645264422440 has 64 divisors (see below), whose sum is σ = 1584530112960. Its totient is φ = 234538014720.

The previous prime is 645264422431. The next prime is 645264422441. The reversal of 645264422440 is 44224462546.

It is not an unprimeable number, because it can be changed into a prime (645264422441) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 677527 + ... + 1322713.

It is an arithmetic number, because the mean of its divisors is an integer number (24758283015).

Almost surely, 2^645264422440 is an apocalyptic number.

It is an amenable number.

645264422440 is an abundant number, since it is smaller than the sum of its proper divisors (939265690520).

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

645264422440 is a wasteful number, since it uses less digits than its factorization.

645264422440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 647482 (or 647478 counting only the distinct ones).

The product of its (nonzero) digits is 1474560, while the sum is 43.

Adding to 645264422440 its reverse (44224462546), we get a palindrome (689488884986).

The spelling of 645264422440 in words is "six hundred forty-five billion, two hundred sixty-four million, four hundred twenty-two thousand, four hundred forty".