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19990 = 251999
BaseRepresentation
bin100111000010110
31000102101
410320112
51114430
6232314
7112165
oct47026
930371
1019990
1114023
12b69a
139139
1473dc
155dca
hex4e16

19990 has 8 divisors (see below), whose sum is σ = 36000. Its totient is φ = 7992.

The previous prime is 19979. The next prime is 19991. The reversal of 19990 is 9991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 990 + ... + 1009.

It is an arithmetic number, because the mean of its divisors is an integer number (4500).

219990 is an apocalyptic number.

19990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

19990 is a deficient number, since it is larger than the sum of its proper divisors (16010).

19990 is a wasteful number, since it uses less digits than its factorization.

19990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2006.

The product of its (nonzero) digits is 729, while the sum is 28.

The square root of 19990 is about 141.3859964777. The cubic root of 19990 is about 27.1396513824.

Subtracting from 19990 its reverse (9991), we obtain a palindrome (9999).

It can be divided in two parts, 199 and 90, that added together give a square (289 = 172).

The spelling of 19990 in words is "nineteen thousand, nine hundred ninety".

Divisors: 1 2 5 10 1999 3998 9995 19990