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212780 = 22510639
BaseRepresentation
bin110011111100101100
3101210212202
4303330230
523302110
64321032
71544231
oct637454
9353782
10212780
11135957
12a3178
1375b09
1457788
15430a5
hex33f2c

212780 has 12 divisors (see below), whose sum is σ = 446880. Its totient is φ = 85104.

The previous prime is 212777. The next prime is 212791. The reversal of 212780 is 87212.

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 10639 = 212780 / (2 + 1 + 2 + 7 + 8 + 0).

It is a plaindrome in base 14.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5300 + ... + 5339.

It is an arithmetic number, because the mean of its divisors is an integer number (37240).

2212780 is an apocalyptic number.

212780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

212780 is an abundant number, since it is smaller than the sum of its proper divisors (234100).

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

212780 is a wasteful number, since it uses less digits than its factorization.

212780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10648 (or 10646 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 20.

The square root of 212780 is about 461.2808255282. The cubic root of 212780 is about 59.7003579200.

Adding to 212780 its reverse (87212), we get a palindrome (299992).

The spelling of 212780 in words is "two hundred twelve thousand, seven hundred eighty".

Divisors: 1 2 4 5 10 20 10639 21278 42556 53195 106390 212780