1581720540550 has 12 divisors (see below), whose sum is σ = 2942000205516. Its totient is φ = 632688216200.

The previous prime is 1581720540493. The next prime is 1581720540551. The reversal of 1581720540550 is 550450271851.

It is a junction number, because it is equal to n+sod(n) for n = 1581720540497 and 1581720540506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1581720540551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 15817205356 + ... + 15817205455.

It is an arithmetic number, because the mean of its divisors is an integer number (245166683793).

Almost surely, 2^{1581720540550} is an apocalyptic number.

1581720540550 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1581720540550 is a deficient number, since it is larger than the sum of its proper divisors (1360279664966).

1581720540550 is a wasteful number, since it uses less digits than its factorization.

1581720540550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31634410823 (or 31634410818 counting only the distinct ones).

The product of its (nonzero) digits is 280000, while the sum is 43.

The spelling of 1581720540550 in words is "one trillion, five hundred eighty-one billion, seven hundred twenty million, five hundred forty thousand, five hundred fifty".