1581943617387 has 24 divisors (see below), whose sum is σ = 2612112353760. Its totient is φ = 903742824960.

The previous prime is 1581943617383. The next prime is 1581943617437. The reversal of 1581943617387 is 7837163491851.

1581943617387 is a `hidden beast` number, since 1 + 5 + 8 + 1 + 9 + 4 + 3 + 617 + 3 + 8 + 7 = 666.

It is not a de Polignac number, because 1581943617387 - 2² = 1581943617383 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (1581943617383) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2869062 + ... + 3375707.

It is an arithmetic number, because the mean of its divisors is an integer number (108838014740).

Almost surely, 2^{1581943617387} is an apocalyptic number.

1581943617387 is a deficient number, since it is larger than the sum of its proper divisors (1030168736373).

1581943617387 is a wasteful number, since it uses less digits than its factorization.

1581943617387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6248803 (or 6248800 counting only the distinct ones).

The product of its digits is 30481920, while the sum is 63.

The spelling of 1581943617387 in words is "one trillion, five hundred eighty-one billion, nine hundred forty-three million, six hundred seventeen thousand, three hundred eighty-seven".