641654388 has 18 divisors (see below), whose sum is σ = 1621959794. Its totient is φ = 213884784.

The previous prime is 641654381. The next prime is 641654393. The reversal of 641654388 is 883456146.

641654388 is nontrivially palindromic in base 8.

It can be written as a sum of positive squares in only one way, i.e., 616131684 + 25522704 = 24822^2 + 5052^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641654381) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8911831 + ... + 8911902.

Almost surely, 2^641654388 is an apocalyptic number.

It is an amenable number.

641654388 is an abundant number, since it is smaller than the sum of its proper divisors (980305406).

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

641654388 is a wasteful number, since it uses less digits than its factorization.

641654388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17823743 (or 17823738 counting only the distinct ones).

The product of its digits is 552960, while the sum is 45.

The square root of 641654388 is about 25330.8978917053. The cubic root of 641654388 is about 862.5157935356.

The spelling of 641654388 in words is "six hundred forty-one million, six hundred fifty-four thousand, three hundred eighty-eight".