661771332 has 18 divisors (see below), whose sum is σ = 1672810958. Its totient is φ = 220590432.

The previous prime is 661771321. The next prime is 661771351. The reversal of 661771332 is 233177166.

661771332 is a `hidden beast` number, since 6 + 617 + 7 + 1 + 3 + 32 = 666.

It can be written as a sum of positive squares in only one way, i.e., 531948096 + 129823236 = 23064^2 + 11394^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 18382537 = 661771332 / (6 + 6 + 1 + 7 + 7 + 1 + 3 + 3 + 2).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9191233 + ... + 9191304.

Almost surely, 2^661771332 is an apocalyptic number.

It is an amenable number.

661771332 is an abundant number, since it is smaller than the sum of its proper divisors (1011039626).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661771332 is a wasteful number, since it uses less digits than its factorization.

661771332 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18382547 (or 18382542 counting only the distinct ones).

The product of its digits is 31752, while the sum is 36.

The square root of 661771332 is about 25724.9165596314. The cubic root of 661771332 is about 871.4369752277.

The spelling of 661771332 in words is "six hundred sixty-one million, seven hundred seventy-one thousand, three hundred thirty-two".