2156551661233 has 4 divisors (see below), whose sum is σ = 2156795045748. Its totient is φ = 2156308276720.

The previous prime is 2156551661183. The next prime is 2156551661237. The reversal of 2156551661233 is 3321661556512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1119315332529 + 1037236328704 = 1057977^2 + 1018448^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2156551661233 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2156551661237) 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, 121678966 + ... + 121696687.

It is an arithmetic number, because the mean of its divisors is an integer number (539198761437).

Almost surely, 2^{2156551661233} is an apocalyptic number.

It is an amenable number.

2156551661233 is a deficient number, since it is larger than the sum of its proper divisors (243384515).

2156551661233 is an equidigital number, since it uses as much as digits as its factorization.

2156551661233 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 243384514.

The product of its digits is 972000, while the sum is 46.

The spelling of 2156551661233 in words is "two trillion, one hundred fifty-six billion, five hundred fifty-one million, six hundred sixty-one thousand, two hundred thirty-three".