660257021 has 8 divisors (see below), whose sum is σ = 689290560. Its totient is φ = 631250752.

The previous prime is 660257009. The next prime is 660257027. The reversal of 660257021 is 120752066.

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 660257021 - 2²² = 656062717 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 (660257027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 54506 + ... + 65508.

It is an arithmetic number, because the mean of its divisors is an integer number (86161320).

Almost surely, 2^660257021 is an apocalyptic number.

It is an amenable number.

660257021 is a deficient number, since it is larger than the sum of its proper divisors (29033539).

660257021 is a wasteful number, since it uses less digits than its factorization.

660257021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13635.

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 660257021 is about 25695.4669348506. The cubic root of 660257021 is about 870.7717734333.

The spelling of 660257021 in words is "six hundred sixty million, two hundred fifty-seven thousand, twenty-one".