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21418390 = 257243711
BaseRepresentation
bin101000110110…
…1000110010110
31111022011111201
41101231012112
520440342030
62043023114
7350024200
oct121550626
944264451
1021418390
11110a9a54
12720aa9a
13458bc06
142bb7770
151d312ca
hex146d196

21418390 has 24 divisors (see below), whose sum is σ = 44848512. Its totient is φ = 7343280.

The previous prime is 21418379. The next prime is 21418403. The reversal of 21418390 is 9381412.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21366 + ... + 22345.

It is an arithmetic number, because the mean of its divisors is an integer number (1868688).

Almost surely, 221418390 is an apocalyptic number.

21418390 is an abundant number, since it is smaller than the sum of its proper divisors (23430122).

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

21418390 is a wasteful number, since it uses less digits than its factorization.

21418390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43732 (or 43725 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 21418390 is about 4628.0006482281. Note that the first 3 decimals coincide. The cubic root of 21418390 is about 277.7126147000.

The spelling of 21418390 in words is "twenty-one million, four hundred eighteen thousand, three hundred ninety".

Divisors: 1 2 5 7 10 14 35 49 70 98 245 490 43711 87422 218555 305977 437110 611954 1529885 2141839 3059770 4283678 10709195 21418390