1944655351081 has 3 divisors (see below), whose sum is σ = 1944656745591. Its totient is φ = 1944653956572.

The previous prime is 1944655351073. The next prime is 1944655351091. The reversal of 1944655351081 is 1801535564491.

The square root of 1944655351081 is 1394509.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 1144238835481 + 800416515600 = 1069691^2 + 894660^2 .

It is not a de Polignac number, because 1944655351081 - 2³ = 1944655351073 is a prime.

It is a super-2 number, since 2×1944655351081² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1944655351061) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 697255 + ... + 2091763.

It is an arithmetic number, because the mean of its divisors is an integer number (648218915197).

Almost surely, 2^{1944655351081} is an apocalyptic number.

1944655351081 is the 1394509-th square number.

1944655351081 is the 697255-th centered octagonal number.

It is an amenable number.

1944655351081 is a deficient number, since it is larger than the sum of its proper divisors (1394510).

1944655351081 is an frugal number, since it uses more digits than its factorization.

1944655351081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2789018 (or 1394509 counting only the distinct ones).

The product of its (nonzero) digits is 2592000, while the sum is 52.

The spelling of 1944655351081 in words is "one trillion, nine hundred forty-four billion, six hundred fifty-five million, three hundred fifty-one thousand, eighty-one".