1556740883681 has 4 divisors (see below), whose sum is σ = 1624425269952. Its totient is φ = 1489056497412.

The previous prime is 1556740883651. The next prime is 1556740883693. The reversal of 1556740883681 is 1863880476551.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1556740883681 - 2⁶ = 1556740883617 is a prime.

It is a super-2 number, since 2×1556740883681² (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 (1556740883611) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33842193101 + ... + 33842193146.

It is an arithmetic number, because the mean of its divisors is an integer number (406106317488).

Almost surely, 2^{1556740883681} is an apocalyptic number.

It is an amenable number.

1556740883681 is a deficient number, since it is larger than the sum of its proper divisors (67684386271).

1556740883681 is an equidigital number, since it uses as much as digits as its factorization.

1556740883681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67684386270.

The product of its (nonzero) digits is 38707200, while the sum is 62.

The spelling of 1556740883681 in words is "one trillion, five hundred fifty-six billion, seven hundred forty million, eight hundred eighty-three thousand, six hundred eighty-one".