645065321010 has 128 divisors (see below), whose sum is σ = 1693407513600. Its totient is φ = 155962609920.

The previous prime is 645065321009. The next prime is 645065321027. The reversal of 645065321010 is 10123560546.

It is a super-2 number, since 2×645065321010² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 325954201 + ... + 325956179.

It is an arithmetic number, because the mean of its divisors is an integer number (13229746200).

Almost surely, 2^645065321010 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645065321010, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (846703756800).

645065321010 is an abundant number, since it is smaller than the sum of its proper divisors (1048342192590).

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

645065321010 is a wasteful number, since it uses less digits than its factorization.

645065321010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4136.

The product of its (nonzero) digits is 21600, while the sum is 33.

Adding to 645065321010 its reverse (10123560546), we get a palindrome (655188881556).

The spelling of 645065321010 in words is "six hundred forty-five billion, sixty-five million, three hundred twenty-one thousand, ten".