645510121420 has 24 divisors (see below), whose sum is σ = 1355830517664. Its totient is φ = 258154665216.

The previous prime is 645510121393. The next prime is 645510121453. The reversal of 645510121420 is 24121015546.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2979184 + ... + 3188503.

It is an arithmetic number, because the mean of its divisors is an integer number (56492938236).

Almost surely, 2^645510121420 is an apocalyptic number.

It is an amenable number.

645510121420 is an abundant number, since it is smaller than the sum of its proper divisors (710320396244).

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

645510121420 is a wasteful number, since it uses less digits than its factorization.

645510121420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6172929 (or 6172927 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 31.

Adding to 645510121420 its reverse (24121015546), we get a palindrome (669631136966).

The spelling of 645510121420 in words is "six hundred forty-five billion, five hundred ten million, one hundred twenty-one thousand, four hundred twenty".