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21281372 = 2271495101
BaseRepresentation
bin101000100101…
…1101001011100
31111001012112222
41101023221130
520422000442
62040044512
7345613550
oct121135134
944035488
1021281372
1111016012
127163738
134541738
142b7d860
151d058d2
hex144ba5c

21281372 has 24 divisors (see below), whose sum is σ = 42856800. Its totient is φ = 9057600.

The previous prime is 21281369. The next prime is 21281441. The reversal of 21281372 is 27318212.

It is a congruent number.

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, 1622 + ... + 6722.

It is an arithmetic number, because the mean of its divisors is an integer number (1785700).

Almost surely, 221281372 is an apocalyptic number.

It is an amenable number.

21281372 is an abundant number, since it is smaller than the sum of its proper divisors (21575428).

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

21281372 is a wasteful number, since it uses less digits than its factorization.

21281372 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5261 (or 5259 counting only the distinct ones).

The product of its digits is 1344, while the sum is 26.

The square root of 21281372 is about 4613.1737448312. The cubic root of 21281372 is about 277.1191518221.

Adding to 21281372 its reverse (27318212), we get a palindrome (48599584).

The spelling of 21281372 in words is "twenty-one million, two hundred eighty-one thousand, three hundred seventy-two".

Divisors: 1 2 4 7 14 28 149 298 596 1043 2086 4172 5101 10202 20404 35707 71414 142828 760049 1520098 3040196 5320343 10640686 21281372