644735067473 has 16 divisors (see below), whose sum is σ = 739704754176. Its totient is φ = 550484439120.

The previous prime is 644735067461. The next prime is 644735067491. The reversal of 644735067473 is 374760537446.

It is a happy number.

It is not a de Polignac number, because 644735067473 - 2¹² = 644735063377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644735067073) 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, 2575040 + ... + 2814302.

It is an arithmetic number, because the mean of its divisors is an integer number (46231547136).

Almost surely, 2^644735067473 is an apocalyptic number.

It is an amenable number.

644735067473 is a deficient number, since it is larger than the sum of its proper divisors (94969686703).

644735067473 is a wasteful number, since it uses less digits than its factorization.

644735067473 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240764.

The product of its (nonzero) digits is 35562240, while the sum is 56.

The spelling of 644735067473 in words is "six hundred forty-four billion, seven hundred thirty-five million, sixty-seven thousand, four hundred seventy-three".