6661993785 has 16 divisors (see below), whose sum is σ = 10660750080. Its totient is φ = 3552543360.

The previous prime is 6661993759. The next prime is 6661993801. The reversal of 6661993785 is 5873991666.

6661993785 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 6661993785 - 2¹² = 6661989689 is a prime.

It is a super-2 number, since 2×6661993785² = 88764322382757252450, which contains 22 as substring.

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, 87765 + ... + 145005.

It is an arithmetic number, because the mean of its divisors is an integer number (666296880).

Almost surely, 2^6661993785 is an apocalyptic number.

It is an amenable number.

6661993785 is a deficient number, since it is larger than the sum of its proper divisors (3998756295).

6661993785 is a wasteful number, since it uses less digits than its factorization.

6661993785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65008.

The product of its digits is 14696640, while the sum is 60.

The square root of 6661993785 is about 81621.0376373641. The cubic root of 6661993785 is about 1881.6322199798.

The spelling of 6661993785 in words is "six billion, six hundred sixty-one million, nine hundred ninety-three thousand, seven hundred eighty-five".