646566900 has 144 divisors (see below), whose sum is σ = 2153195520. Its totient is φ = 146736000.

The previous prime is 646566887. The next prime is 646566911. The reversal of 646566900 is 9665646.

It is a super-2 number, since 2×646566900² = 836097512351220000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 316081 + ... + 318119.

Almost surely, 2^646566900 is an apocalyptic number.

646566900 is a gapful number since it is divisible by the number (60) 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 646566900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1076597760).

646566900 is an abundant number, since it is smaller than the sum of its proper divisors (1506628620).

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

646566900 is a wasteful number, since it uses less digits than its factorization.

646566900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2214 (or 2207 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 42.

The square root of 646566900 is about 25427.6797997772. The cubic root of 646566900 is about 864.7113429789.

The spelling of 646566900 in words is "six hundred forty-six million, five hundred sixty-six thousand, nine hundred".