644700546 has 120 divisors (see below), whose sum is σ = 1692441036. Its totient is φ = 182891520.

The previous prime is 644700527. The next prime is 644700559. The reversal of 644700546 is 645007446.

644700546 is a `hidden beast` number, since 6 + 44 + 70 + 0 + 546 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 644601321 + 99225 = 25389^2 + 315^2 .

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 644700546.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 1912890 + ... + 1913226.

Almost surely, 2^644700546 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644700546, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (846220518).

644700546 is an abundant number, since it is smaller than the sum of its proper divisors (1047740490).

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

644700546 is a wasteful number, since it uses less digits than its factorization.

644700546 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 606 (or 590 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 36.

The square root of 644700546 is about 25390.9540190990. The cubic root of 644700546 is about 863.8785274828.

The spelling of 644700546 in words is "six hundred forty-four million, seven hundred thousand, five hundred forty-six".