644923031041 has 9 divisors (see below), whose sum is σ = 647113982211. Its totient is φ = 642739480992.

The previous prime is 644923031021. The next prime is 644923031047. The reversal of 644923031041 is 140130329446.

The square root of 644923031041 is 803071.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 173909850625 + 471013180416 = 417025^2 + 686304^2 .

It is not a de Polignac number, because 644923031041 - 2¹⁷ = 644922899969 is a prime.

It is a super-2 number, since 2×644923031041² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644923031047) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 270633736 + ... + 270636118.

It is an arithmetic number, because the mean of its divisors is an integer number (71901553579).

Almost surely, 2^644923031041 is an apocalyptic number.

644923031041 is the 803071-st square number.

644923031041 is the 401536-th centered octagonal number.

It is an amenable number.

644923031041 is a deficient number, since it is larger than the sum of its proper divisors (2190951170).

644923031041 is an frugal number, since it uses more digits than its factorization.

644923031041 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5440 (or 2720 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 37.

The spelling of 644923031041 in words is "six hundred forty-four billion, nine hundred twenty-three million, thirty-one thousand, forty-one".