645651000 has 192 divisors, whose sum is σ = 2263978080. Its totient is φ = 172108800.

The previous prime is 645650953. The next prime is 645651011. The reversal of 645651000 is 156546.

It is a happy number.

645651000 is a `hidden beast` number, since 6 + 4 + 5 + 651 + 0 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

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 47 ways as a sum of consecutive naturals, for example, 241672 + ... + 244328.

Almost surely, 2^645651000 is an apocalyptic number.

645651000 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 645651000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1131989040).

645651000 is an abundant number, since it is smaller than the sum of its proper divisors (1618327080).

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

645651000 is a wasteful number, since it uses less digits than its factorization.

645651000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2693 (or 2667 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 645651000 is about 25409.6635160720. The cubic root of 645651000 is about 864.3028452246.

The spelling of 645651000 in words is "six hundred forty-five million, six hundred fifty-one thousand".