1556001551161 has 4 divisors (see below), whose sum is σ = 1556005033552. Its totient is φ = 1555998068772.

The previous prime is 1556001551141. The next prime is 1556001551189. The reversal of 1556001551161 is 1611551006551.

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 a cyclic number.

It is not a de Polignac number, because 1556001551161 - 2²⁵ = 1555967996729 is a prime.

It is a super-2 number, since 2×1556001551161² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1556001551161.

It is not an unprimeable number, because it can be changed into a prime (1556001551131) 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, 951615 + ... + 2004388.

It is an arithmetic number, because the mean of its divisors is an integer number (389001258388).

Almost surely, 2^{1556001551161} is an apocalyptic number.

It is an amenable number.

1556001551161 is a deficient number, since it is larger than the sum of its proper divisors (3482391).

1556001551161 is an equidigital number, since it uses as much as digits as its factorization.

1556001551161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3482390.

The product of its (nonzero) digits is 22500, while the sum is 37.

The spelling of 1556001551161 in words is "one trillion, five hundred fifty-six billion, one million, five hundred fifty-one thousand, one hundred sixty-one".