6561793994 has 32 divisors (see below), whose sum is σ = 12294706176. Its totient is φ = 2561391360.

The previous prime is 6561793951. The next prime is 6561794009. The reversal of 6561793994 is 4993971656.

It is a Smith number, since the sum of its digits (59) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 437309 + ... + 452064.

It is an arithmetic number, because the mean of its divisors is an integer number (384209568).

Almost surely, 2^6561793994 is an apocalyptic number.

6561793994 is a deficient number, since it is larger than the sum of its proper divisors (5732912182).

6561793994 is a wasteful number, since it uses less digits than its factorization.

6561793994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 889430.

The product of its digits is 11022480, while the sum is 59.

The square root of 6561793994 is about 81004.9010492575. The cubic root of 6561793994 is about 1872.1509554910.

The spelling of 6561793994 in words is "six billion, five hundred sixty-one million, seven hundred ninety-three thousand, nine hundred ninety-four".