644630623322253 has 8 divisors (see below), whose sum is σ = 865276004460000. Its totient is φ = 426869495533008.

The previous prime is 644630623322239. The next prime is 644630623322311. The reversal of 644630623322253 is 352223326036446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 644630623322253 - 2¹³ = 644630623314061 is a prime.

It is a super-2 number, since 2×644630623322253² (a number of 30 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 644630623322196 and 644630623322205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644630623322953) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 721063336603 + ... + 721063337496.

It is an arithmetic number, because the mean of its divisors is an integer number (108159500557500).

Almost surely, 2^{644630623322253} is an apocalyptic number.

It is an amenable number.

644630623322253 is a deficient number, since it is larger than the sum of its proper divisors (220645381137747).

644630623322253 is a wasteful number, since it uses less digits than its factorization.

644630623322253 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1442126674251.

The product of its (nonzero) digits is 22394880, while the sum is 51.

Adding to 644630623322253 its reverse (352223326036446), we get a palindrome (996853949358699).

The spelling of 644630623322253 in words is "six hundred forty-four trillion, six hundred thirty billion, six hundred twenty-three million, three hundred twenty-two thousand, two hundred fifty-three".