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20213731 = 173493407
BaseRepresentation
bin100110100011…
…0111111100011
31102000222000201
41031012333203
520133314411
62001130031
7333546106
oct115067743
942028021
1020213731
111045696a
126929917
1342597b5
14298273d
151b943c1
hex1346fe3

20213731 has 8 divisors (see below), whose sum is σ = 21470400. Its totient is φ = 18964608.

The previous prime is 20213719. The next prime is 20213747. The reversal of 20213731 is 13731202.

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 20213731 - 27 = 20213603 is a prime.

It is a super-2 number, since 2×202137312 = 817189841880722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20213699 and 20213708.

It is not an unprimeable number, because it can be changed into a prime (20213761) 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, 4230 + ... + 7636.

It is an arithmetic number, because the mean of its divisors is an integer number (2683800).

Almost surely, 220213731 is an apocalyptic number.

20213731 is the 2844-th centered pentagonal number.

20213731 is a deficient number, since it is larger than the sum of its proper divisors (1256669).

20213731 is a wasteful number, since it uses less digits than its factorization.

20213731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3773.

The product of its (nonzero) digits is 252, while the sum is 19.

The square root of 20213731 is about 4495.9683050484. The cubic root of 20213731 is about 272.4052629181.

Adding to 20213731 its reverse (13731202), we get a palindrome (33944933).

The spelling of 20213731 in words is "twenty million, two hundred thirteen thousand, seven hundred thirty-one".

Divisors: 1 17 349 3407 5933 57919 1189043 20213731