660421836 has 120 divisors (see below), whose sum is σ = 1844156160. Its totient is φ = 205480800.

The previous prime is 660421781. The next prime is 660421847. The reversal of 660421836 is 638124066.

660421836 is a `hidden beast` number, since 6 + 604 + 2 + 18 + 36 = 666.

It is a super-2 number, since 2×660421836² = 872314002931221792, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 660421836.

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 39 ways as a sum of consecutive naturals, for example, 436321 + ... + 437831.

It is an arithmetic number, because the mean of its divisors is an integer number (15367968).

Almost surely, 2^660421836 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 660421836, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (922078080).

660421836 is an abundant number, since it is smaller than the sum of its proper divisors (1183734324).

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

660421836 is a wasteful number, since it uses less digits than its factorization.

660421836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1617 (or 1606 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The square root of 660421836 is about 25698.6738179230. The cubic root of 660421836 is about 870.8442221441.

The spelling of 660421836 in words is "six hundred sixty million, four hundred twenty-one thousand, eight hundred thirty-six".