645454656 has 504 divisors, whose sum is σ = 2459329600. Its totient is φ = 167650560.

The previous prime is 645454637. The next prime is 645454661. The reversal of 645454656 is 656454546.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

645454656 is a `hidden beast` number, since 6 + 4 + 54 + 546 + 56 = 666.

It is a tau number, because it is divible by the number of its divisors (504).

It is a super-2 number, since 2×645454656² = 833223425904156672, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 58677691 + ... + 58677701.

Almost surely, 2^645454656 is an apocalyptic number.

645454656 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645454656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1229664800).

645454656 is an abundant number, since it is smaller than the sum of its proper divisors (1813874944).

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

645454656 is an equidigital number, since it uses as much as digits as its factorization.

645454656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70 (or 23 counting only the distinct ones).

The product of its digits is 1728000, while the sum is 45.

The square root of 645454656 is about 25405.7996528352. The cubic root of 645454656 is about 864.2152241605.

The spelling of 645454656 in words is "six hundred forty-five million, four hundred fifty-four thousand, six hundred fifty-six".