1656561943 has 2 divisors, whose sum is σ = 1656561944. Its totient is φ = 1656561942.

The previous prime is 1656561931. The next prime is 1656562001. The reversal of 1656561943 is 3491656561.

It is a weak prime.

It is an emirp because it is prime and its reverse (3491656561) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1656561943 - 2²⁹ = 1119691031 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1656561893 and 1656561902.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1656561443) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 828280971 + 828280972.

It is an arithmetic number, because the mean of its divisors is an integer number (828280972).

Almost surely, 2^1656561943 is an apocalyptic number.

1656561943 is a deficient number, since it is larger than the sum of its proper divisors (1).

1656561943 is an equidigital number, since it uses as much as digits as its factorization.

1656561943 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 583200, while the sum is 46.

The square root of 1656561943 is about 40700.8838110427. The cubic root of 1656561943 is about 1183.2301478145.

The spelling of 1656561943 in words is "one billion, six hundred fifty-six million, five hundred sixty-one thousand, nine hundred forty-three".