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640191204 = 223242172
BaseRepresentation
bin100110001010001…
…000101011100100
31122121122002020100
4212022020223210
52302342104304
6143305304100
721602351442
oct4612105344
91577562210
10640191204
112a940a144
1215a495030
13a282b483
1461049b92
153b30b439
hex26288ae4

640191204 has 27 divisors (see below), whose sum is σ = 1618644937. Its totient is φ = 213346464.

The previous prime is 640191197. The next prime is 640191221. The reversal of 640191204 is 402191046.

The square root of 640191204 is 25302.

It is a perfect power (a square), and thus also a powerful number.

640191204 is a `hidden beast` number, since 640 + 1 + 9 + 12 + 0 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 568822500 + 71368704 = 23850^2 + 8448^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 149704 + ... + 153920.

Almost surely, 2640191204 is an apocalyptic number.

640191204 is the 25302-nd square number.

It is an amenable number.

640191204 is an abundant number, since it is smaller than the sum of its proper divisors (978453733).

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

640191204 is an equidigital number, since it uses as much as digits as its factorization.

640191204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8444 (or 4222 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The cubic root of 640191204 is about 861.8596875783.

It can be divided in two parts, 640 and 191204, that added together give a square (191844 = 4382).

The spelling of 640191204 in words is "six hundred forty million, one hundred ninety-one thousand, two hundred four".

Divisors: 1 2 3 4 6 9 12 18 36 4217 8434 12651 16868 25302 37953 50604 75906 151812 17783089 35566178 53349267 71132356 106698534 160047801 213397068 320095602 640191204