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20780939 = 371972851
BaseRepresentation
bin100111101000…
…1011110001011
31110002210002102
41033101132023
520304442224
62021224015
7341430554
oct117213613
943083072
1020780939
1110804033
126b6200b
1343c7a1a
142a8d32b
151c574ae
hex13d178b

20780939 has 8 divisors (see below), whose sum is σ = 21458448. Its totient is φ = 20109600.

The previous prime is 20780887. The next prime is 20780941. The reversal of 20780939 is 93908702.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2k-20780939 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20780999) 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, 5864 + ... + 8714.

It is an arithmetic number, because the mean of its divisors is an integer number (2682306).

Almost surely, 220780939 is an apocalyptic number.

20780939 is a deficient number, since it is larger than the sum of its proper divisors (677509).

20780939 is a wasteful number, since it uses less digits than its factorization.

20780939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3085.

The product of its (nonzero) digits is 27216, while the sum is 38.

The square root of 20780939 is about 4558.6115210665. The cubic root of 20780939 is about 274.9297407288.

The spelling of 20780939 in words is "twenty million, seven hundred eighty thousand, nine hundred thirty-nine".

Divisors: 1 37 197 2851 7289 105487 561647 20780939