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20981487 = 38384263
BaseRepresentation
bin101000000001…
…0011011101111
31110110222012010
41100002123233
520332401422
62025412303
7343224342
oct120023357
943428163
1020981487
111093077a
12703a093
1344680a7
142b02459
151c96b0c
hex14026ef

20981487 has 8 divisors (see below), whose sum is σ = 28312704. Its totient is φ = 13818968.

The previous prime is 20981473. The next prime is 20981507. The reversal of 20981487 is 78418902.

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

It is a cyclic number.

It is not a de Polignac number, because 20981487 - 28 = 20981231 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20981407) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41883 + ... + 42380.

It is an arithmetic number, because the mean of its divisors is an integer number (3539088).

Almost surely, 220981487 is an apocalyptic number.

20981487 is a deficient number, since it is larger than the sum of its proper divisors (7331217).

20981487 is an equidigital number, since it uses as much as digits as its factorization.

20981487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84349.

The product of its (nonzero) digits is 32256, while the sum is 39.

The square root of 20981487 is about 4580.5553156795. Note that the first 3 decimals coincide. The cubic root of 20981487 is about 275.8113208450.

The spelling of 20981487 in words is "twenty million, nine hundred eighty-one thousand, four hundred eighty-seven".

Divisors: 1 3 83 249 84263 252789 6993829 20981487