644154066 has 16 divisors (see below), whose sum is σ = 1431453600. Its totient is φ = 214718004.

The previous prime is 644154037. The next prime is 644154073. The reversal of 644154066 is 660451446.

644154066 is a `hidden beast` number, since 644 + 1 + 5 + 4 + 0 + 6 + 6 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 644154066.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5964336 + ... + 5964443.

It is an arithmetic number, because the mean of its divisors is an integer number (89465850).

Almost surely, 2^644154066 is an apocalyptic number.

644154066 is an abundant number, since it is smaller than the sum of its proper divisors (787299534).

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

644154066 is a wasteful number, since it uses less digits than its factorization.

644154066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11928790 (or 11928784 counting only the distinct ones).

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

The square root of 644154066 is about 25380.1904248175. The cubic root of 644154066 is about 863.6343697918.

The spelling of 644154066 in words is "six hundred forty-four million, one hundred fifty-four thousand, sixty-six".