661368671 has 4 divisors (see below), whose sum is σ = 662302200. Its totient is φ = 660435144.

The previous prime is 661368667. The next prime is 661368677. The reversal of 661368671 is 176863166.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 176863166 = 2 ⋅88431583.

It is a cyclic number.

It is not a de Polignac number, because 661368671 - 2² = 661368667 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661368677) 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, 465701 + ... + 467118.

It is an arithmetic number, because the mean of its divisors is an integer number (165575550).

Almost surely, 2^661368671 is an apocalyptic number.

661368671 is a deficient number, since it is larger than the sum of its proper divisors (933529).

661368671 is an equidigital number, since it uses as much as digits as its factorization.

661368671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 933528.

The product of its digits is 217728, while the sum is 44.

The square root of 661368671 is about 25717.0890848867. The cubic root of 661368671 is about 871.2601946898.

The spelling of 661368671 in words is "six hundred sixty-one million, three hundred sixty-eight thousand, six hundred seventy-one".