661584777 has 8 divisors (see below), whose sum is σ = 1008129216. Its totient is φ = 378048432.

The previous prime is 661584761. The next prime is 661584797. The reversal of 661584777 is 777485166.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 661584777 - 2⁴ = 661584761 is a prime.

It is not an unprimeable number, because it can be changed into a prime (661584757) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15751998 + ... + 15752039.

It is an arithmetic number, because the mean of its divisors is an integer number (126016152).

Almost surely, 2^661584777 is an apocalyptic number.

It is an amenable number.

661584777 is a deficient number, since it is larger than the sum of its proper divisors (346544439).

661584777 is a wasteful number, since it uses less digits than its factorization.

661584777 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31504047.

The product of its digits is 1975680, while the sum is 51.

The square root of 661584777 is about 25721.2903447708. The cubic root of 661584777 is about 871.3550807747.

The spelling of 661584777 in words is "six hundred sixty-one million, five hundred eighty-four thousand, seven hundred seventy-seven".