6557720243 has 4 divisors (see below), whose sum is σ = 6640729440. Its totient is φ = 6474711048.

The previous prime is 6557720237. The next prime is 6557720269. The reversal of 6557720243 is 3420277556.

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

It is a cyclic number.

It is not a de Polignac number, because 6557720243 - 2⁶ = 6557720179 is a prime.

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 6557720243.

It is not an unprimeable number, because it can be changed into a prime (6557726243) 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, 41504480 + ... + 41504637.

It is an arithmetic number, because the mean of its divisors is an integer number (1660182360).

Almost surely, 2^6557720243 is an apocalyptic number.

6557720243 is a deficient number, since it is larger than the sum of its proper divisors (83009197).

6557720243 is an equidigital number, since it uses as much as digits as its factorization.

6557720243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83009196.

The product of its (nonzero) digits is 352800, while the sum is 41.

The square root of 6557720243 is about 80979.7520556836. The cubic root of 6557720243 is about 1871.7634468480.

Adding to 6557720243 its reverse (3420277556), we get a palindrome (9977997799).

The spelling of 6557720243 in words is "six billion, five hundred fifty-seven million, seven hundred twenty thousand, two hundred forty-three".