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20287556981 is a prime number
BaseRepresentation
bin10010111001001110…
…111000110101110101
31221100212121200021022
4102321032320311311
5313022103310411
613153040430525
71315513250306
oct227116706565
957325550238
1020287556981
11867088491a
123b22318445
131bb4139bb3
14da657a7ad
157db11cedb
hex4b93b8d75

20287556981 has 2 divisors, whose sum is σ = 20287556982. Its totient is φ = 20287556980.

The previous prime is 20287556963. The next prime is 20287557007. The reversal of 20287556981 is 18965578202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20161444081 + 126112900 = 141991^2 + 11230^2 .

It is a cyclic number.

It is not a de Polignac number, because 20287556981 - 234 = 3107687797 is a prime.

It is a super-2 number, since 2×202875569812 (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20287556911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10143778490 + 10143778491.

It is an arithmetic number, because the mean of its divisors is an integer number (10143778491).

Almost surely, 220287556981 is an apocalyptic number.

It is an amenable number.

20287556981 is a deficient number, since it is larger than the sum of its proper divisors (1).

20287556981 is an equidigital number, since it uses as much as digits as its factorization.

20287556981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2419200, while the sum is 53.

The spelling of 20287556981 in words is "twenty billion, two hundred eighty-seven million, five hundred fifty-six thousand, nine hundred eighty-one".