645606561444 has 24 divisors (see below), whose sum is σ = 1622293411200. Its totient is φ = 198648172704.

The previous prime is 645606561389. The next prime is 645606561451. The reversal of 645606561444 is 444165606546.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2069251644 + ... + 2069251955.

It is an arithmetic number, because the mean of its divisors is an integer number (67595558800).

Almost surely, 2^645606561444 is an apocalyptic number.

It is an amenable number.

645606561444 is an abundant number, since it is smaller than the sum of its proper divisors (976686849756).

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

645606561444 is a wasteful number, since it uses less digits than its factorization.

645606561444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4138503619 (or 4138503617 counting only the distinct ones).

The product of its (nonzero) digits is 8294400, while the sum is 51.

The spelling of 645606561444 in words is "six hundred forty-five billion, six hundred six million, five hundred sixty-one thousand, four hundred forty-four".