661793138 has 8 divisors (see below), whose sum is σ = 992893788. Its totient is φ = 330828544.

The previous prime is 661793131. The next prime is 661793141. The reversal of 661793138 is 831397166.

661793138 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 661672729 + 120409 = 25723^2 + 347^2 .

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

It is not an unprimeable number, because it can be changed into a prime (661793131) 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, 20831 + ... + 41922.

Almost surely, 2^661793138 is an apocalyptic number.

661793138 is a deficient number, since it is larger than the sum of its proper divisors (331100650).

661793138 is a wasteful number, since it uses less digits than its factorization.

661793138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68028.

The product of its digits is 163296, while the sum is 44.

The square root of 661793138 is about 25725.3403864750. The cubic root of 661793138 is about 871.4465466839.

The spelling of 661793138 in words is "six hundred sixty-one million, seven hundred ninety-three thousand, one hundred thirty-eight".