1944423461581 has 8 divisors (see below), whose sum is σ = 1946269848600. Its totient is φ = 1942577244480.

The previous prime is 1944423461551. The next prime is 1944423461597. The reversal of 1944423461581 is 1851643244491.

It can be written as a sum of positive squares in 4 ways, for example, as 154206221481 + 1790217240100 = 392691^2 + 1337990^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1944423461581 is a prime.

It is a super-2 number, since 2×1944423461581² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1944423461551) 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, 44148351 + ... + 44192371.

It is an arithmetic number, because the mean of its divisors is an integer number (243283731075).

Almost surely, 2^{1944423461581} is an apocalyptic number.

It is an amenable number.

1944423461581 is a deficient number, since it is larger than the sum of its proper divisors (1846387019).

1944423461581 is a wasteful number, since it uses less digits than its factorization.

1944423461581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84959.

The product of its digits is 3317760, while the sum is 52.

The spelling of 1944423461581 in words is "one trillion, nine hundred forty-four billion, four hundred twenty-three million, four hundred sixty-one thousand, five hundred eighty-one".