1656640543 has 2 divisors, whose sum is σ = 1656640544. Its totient is φ = 1656640542.

The previous prime is 1656640519. The next prime is 1656640549. The reversal of 1656640543 is 3450466561.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1656640543 - 2⁵ = 1656640511 is a prime.

It is a super-2 number, since 2×1656640543² = 5488915777422669698, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1656640496 and 1656640505.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1656640549) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 828320271 + 828320272.

It is an arithmetic number, because the mean of its divisors is an integer number (828320272).

Almost surely, 2^1656640543 is an apocalyptic number.

1656640543 is a deficient number, since it is larger than the sum of its proper divisors (1).

1656640543 is an equidigital number, since it uses as much as digits as its factorization.

1656640543 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 259200, while the sum is 40.

The square root of 1656640543 is about 40701.8493805871. The cubic root of 1656640543 is about 1183.2488613553.

The spelling of 1656640543 in words is "one billion, six hundred fifty-six million, six hundred forty thousand, five hundred forty-three".