1581454638481 has 3 divisors (see below), whose sum is σ = 1581455896041. Its totient is φ = 1581453380922.

The previous prime is 1581454638479. The next prime is 1581454638527. The reversal of 1581454638481 is 1848364541851.

It is a happy number.

The square root of 1581454638481 is 1257559.

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 is not a de Polignac number, because 1581454638481 - 2¹ = 1581454638479 is a prime.

It is a super-3 number, since 3×1581454638481³ (a number of 38 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1581454638451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 628780 + ... + 1886338.

It is an arithmetic number, because the mean of its divisors is an integer number (527151965347).

Almost surely, 2^{1581454638481} is an apocalyptic number.

1581454638481 is the 1257559-th square number.

1581454638481 is the 628780-th centered octagonal number.

It is an amenable number.

1581454638481 is a deficient number, since it is larger than the sum of its proper divisors (1257560).

1581454638481 is an frugal number, since it uses more digits than its factorization.

1581454638481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2515118 (or 1257559 counting only the distinct ones).

The product of its digits is 14745600, while the sum is 58.

The spelling of 1581454638481 in words is "one trillion, five hundred eighty-one billion, four hundred fifty-four million, six hundred thirty-eight thousand, four hundred eighty-one".