660465021 has 4 divisors (see below), whose sum is σ = 880620032. Its totient is φ = 440310012.

The previous prime is 660464989. The next prime is 660465037. The reversal of 660465021 is 120564066.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 660465021 - 2⁵ = 660464989 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 660465021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660465721) 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, 110077501 + ... + 110077506.

It is an arithmetic number, because the mean of its divisors is an integer number (220155008).

Almost surely, 2^660465021 is an apocalyptic number.

It is an amenable number.

660465021 is a deficient number, since it is larger than the sum of its proper divisors (220155011).

660465021 is a wasteful number, since it uses less digits than its factorization.

660465021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220155010.

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 660465021 is about 25699.5140226425. The cubic root of 660465021 is about 870.8632032387.

The spelling of 660465021 in words is "six hundred sixty million, four hundred sixty-five thousand, twenty-one".