6557766509 has 32 divisors (see below), whose sum is σ = 8118337536. Its totient is φ = 5175529920.

The previous prime is 6557766487. The next prime is 6557766517. The reversal of 6557766509 is 9056677556.

It is a happy number.

It is not a de Polignac number, because 6557766509 - 2⁸ = 6557766253 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6557766569) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 454484 + ... + 468690.

It is an arithmetic number, because the mean of its divisors is an integer number (253698048).

Almost surely, 2^6557766509 is an apocalyptic number.

It is an amenable number.

6557766509 is a deficient number, since it is larger than the sum of its proper divisors (1560571027).

6557766509 is a wasteful number, since it uses less digits than its factorization.

6557766509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14345.

The product of its (nonzero) digits is 11907000, while the sum is 56.

The square root of 6557766509 is about 80980.0377191811. The cubic root of 6557766509 is about 1871.7678487234.

The spelling of 6557766509 in words is "six billion, five hundred fifty-seven million, seven hundred sixty-six thousand, five hundred nine".