1556638476961 has 16 divisors (see below), whose sum is σ = 1712185993728. Its totient is φ = 1409206489600.

The previous prime is 1556638476949. The next prime is 1556638476973. The reversal of 1556638476961 is 1696748366551.

It is an interprime number because it is at equal distance from previous prime (1556638476949) and next prime (1556638476973).

It is a cyclic number.

It is not a de Polignac number, because 1556638476961 - 2¹³ = 1556638468769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1556638476931) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15678265 + ... + 15777238.

It is an arithmetic number, because the mean of its divisors is an integer number (107011624608).

Almost surely, 2^{1556638476961} is an apocalyptic number.

It is an amenable number.

1556638476961 is a deficient number, since it is larger than the sum of its proper divisors (155547516767).

1556638476961 is a wasteful number, since it uses less digits than its factorization.

1556638476961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31455632.

The product of its digits is 195955200, while the sum is 67.

The spelling of 1556638476961 in words is "one trillion, five hundred fifty-six billion, six hundred thirty-eight million, four hundred seventy-six thousand, nine hundred sixty-one".