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20570731 = 1735379
BaseRepresentation
bin100111001111…
…0001001101011
31102201002201221
41032132021223
520231230411
62012522511
7336563656
oct116361153
942632657
1020570731
1110680105
126a80437
13435313c
142a3689d
151c15071
hex139e26b

20570731 has 16 divisors (see below), whose sum is σ = 22550400. Its totient is φ = 18754944.

The previous prime is 20570729. The next prime is 20570741. The reversal of 20570731 is 13707502.

It is not a de Polignac number, because 20570731 - 21 = 20570729 is a prime.

It is a super-2 number, since 2×205707312 = 846309947748722, 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 = 20570696 and 20570705.

It is not an unprimeable number, because it can be changed into a prime (20570741) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 260350 + ... + 260428.

It is an arithmetic number, because the mean of its divisors is an integer number (1409400).

Almost surely, 220570731 is an apocalyptic number.

20570731 is the 2869-th centered pentagonal number.

20570731 is a deficient number, since it is larger than the sum of its proper divisors (1979669).

20570731 is an frugal number, since it uses more digits than its factorization.

20570731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183 (or 149 counting only the distinct ones).

The product of its (nonzero) digits is 1470, while the sum is 25.

The square root of 20570731 is about 4535.4967754371. The cubic root of 20570731 is about 273.9995870845. Note that the first 3 decimals are identical.

The spelling of 20570731 in words is "twenty million, five hundred seventy thousand, seven hundred thirty-one".

Divisors: 1 17 53 79 289 901 1343 4187 4913 15317 22831 71179 260389 388127 1210043 20570731