661071655 has 8 divisors (see below), whose sum is σ = 835038000. Its totient is φ = 501022656.

The previous prime is 661071641. The next prime is 661071667. The reversal of 661071655 is 556170166.

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

It is a cyclic number.

It is not a de Polignac number, because 661071655 - 2¹⁵ = 661038887 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3479230 + ... + 3479419.

It is an arithmetic number, because the mean of its divisors is an integer number (104379750).

Almost surely, 2^661071655 is an apocalyptic number.

661071655 is a deficient number, since it is larger than the sum of its proper divisors (173966345).

661071655 is a wasteful number, since it uses less digits than its factorization.

661071655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6958673.

The product of its (nonzero) digits is 37800, while the sum is 37.

The square root of 661071655 is about 25711.3137548434. The cubic root of 661071655 is about 871.1297495601.

The spelling of 661071655 in words is "six hundred sixty-one million, seventy-one thousand, six hundred fifty-five".