421664256 has 120 divisors (see below), whose sum is σ = 1310749440. Its totient is φ = 129724416.

The previous prime is 421664251. The next prime is 421664261. The reversal of 421664256 is 652466124.

421664256 is a `hidden beast` number, since 4 + 2 + 1 + 6 + 642 + 5 + 6 = 666.

It is an interprime number because it is at equal distance from previous prime (421664251) and next prime (421664261).

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 421664256.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (421664251) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 56385 + ... + 63423.

It is an arithmetic number, because the mean of its divisors is an integer number (10922912).

Almost surely, 2^421664256 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 421664256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (655374720).

421664256 is an abundant number, since it is smaller than the sum of its proper divisors (889085184).

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

421664256 is a wasteful number, since it uses less digits than its factorization.

421664256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7076 (or 7057 counting only the distinct ones).

The product of its digits is 69120, while the sum is 36.

The square root of 421664256 is about 20534.4650770357. The cubic root of 421664256 is about 749.8750938658.

The spelling of 421664256 in words is "four hundred twenty-one million, six hundred sixty-four thousand, two hundred fifty-six".